/*-------------------------------------------------------------------------
 *
 * pl_exec.c        - Executor for the PL/pgSQL
 *              procedural language
 *
 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * This source code file contains modifications made by THL A29 Limited ("Tencent Modifications").
 * All Tencent Modifications are Copyright (C) 2023 THL A29 Limited.
 *
 * IDENTIFICATION
 *      src/pl/plpgsql/src/pl_exec.c
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include <ctype.h>

#include "access/htup_details.h"
#include "access/transam.h"
#include "access/tupconvert.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "executor/spi.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/planner.h"
#include "parser/parse_coerce.h"
#include "parser/scansup.h"
#include "parser/analyze.h"
#include "storage/proc.h"
#include "tcop/tcopprot.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
#include "utils/typcache.h"
#ifdef XCP
#include "pgxc/pgxc.h"
#endif

#include "plpgsql.h"


typedef struct
{
    int            nargs;            /* number of arguments */
    Oid           *types;            /* types of arguments */
    Datum       *values;            /* evaluated argument values */
    char       *nulls;            /* null markers (' '/'n' style) */
} PreparedParamsData;

/*
 * All plpgsql function executions within a single transaction share the same
 * executor EState for evaluating "simple" expressions.  Each function call
 * creates its own "eval_econtext" ExprContext within this estate for
 * per-evaluation workspace.  eval_econtext is freed at normal function exit,
 * and the EState is freed at transaction end (in case of error, we assume
 * that the abort mechanisms clean it all up).  Furthermore, any exception
 * block within a function has to have its own eval_econtext separate from
 * the containing function's, so that we can clean up ExprContext callbacks
 * properly at subtransaction exit.  We maintain a stack that tracks the
 * individual econtexts so that we can clean up correctly at subxact exit.
 *
 * This arrangement is a bit tedious to maintain, but it's worth the trouble
 * so that we don't have to re-prepare simple expressions on each trip through
 * a function.  (We assume the case to optimize is many repetitions of a
 * function within a transaction.)
 *
 * However, there's no value in trying to amortize simple expression setup
 * across multiple executions of a DO block (inline code block), since there
 * can never be any.  If we use the shared EState for a DO block, the expr
 * state trees are effectively leaked till end of transaction, and that can
 * add up if the user keeps on submitting DO blocks.  Therefore, each DO block
 * has its own simple-expression EState, which is cleaned up at exit from
 * plpgsql_inline_handler().  DO blocks still use the simple_econtext_stack,
 * though, so that subxact abort cleanup does the right thing.
 */
typedef struct SimpleEcontextStackEntry
{
    ExprContext *stack_econtext;    /* a stacked econtext */
    SubTransactionId xact_subxid;    /* ID for current subxact */
    struct SimpleEcontextStackEntry *next;    /* next stack entry up */
} SimpleEcontextStackEntry;

static EState *shared_simple_eval_estate = NULL;
static SimpleEcontextStackEntry *simple_econtext_stack = NULL;

/*
 * Memory management within a plpgsql function generally works with three
 * contexts:
 *
 * 1. Function-call-lifespan data, such as variable values, is kept in the
 * "main" context, a/k/a the "SPI Proc" context established by SPI_connect().
 * This is usually the CurrentMemoryContext while running code in this module
 * (which is not good, because careless coding can easily cause
 * function-lifespan memory leaks, but we live with it for now).
 *
 * 2. Some statement-execution routines need statement-lifespan workspace.
 * A suitable context is created on-demand by get_stmt_mcontext(), and must
 * be reset at the end of the requesting routine.  Error recovery will clean
 * it up automatically.  Nested statements requiring statement-lifespan
 * workspace will result in a stack of such contexts, see push_stmt_mcontext().
 *
 * 3. We use the eval_econtext's per-tuple memory context for expression
 * evaluation, and as a general-purpose workspace for short-lived allocations.
 * Such allocations usually aren't explicitly freed, but are left to be
 * cleaned up by a context reset, typically done by exec_eval_cleanup().
 *
 * These macros are for use in making short-lived allocations:
 */
#define get_eval_mcontext(estate) \
    ((estate)->eval_econtext->ecxt_per_tuple_memory)
#define eval_mcontext_alloc(estate, sz) \
    MemoryContextAlloc(get_eval_mcontext(estate), sz)
#define eval_mcontext_alloc0(estate, sz) \
    MemoryContextAllocZero(get_eval_mcontext(estate), sz)

#ifdef __OPENTENBASE__
extern int PGDLLIMPORT g_in_plpgsql_exec_fun;
extern bool PGDLLIMPORT PlpgsqlDebugPrint;
#endif

/*
 * We use a session-wide hash table for caching cast information.
 *
 * Once built, the compiled expression trees (cast_expr fields) survive for
 * the life of the session.  At some point it might be worth invalidating
 * those after pg_cast changes, but for the moment we don't bother.
 *
 * The evaluation state trees (cast_exprstate) are managed in the same way as
 * simple expressions (i.e., we assume cast expressions are always simple).
 *
 * As with simple expressions, DO blocks don't use the shared hash table but
 * must have their own.  This isn't ideal, but we don't want to deal with
 * multiple simple_eval_estates within a DO block.
 */
typedef struct                    /* lookup key for cast info */
{
    /* NB: we assume this struct contains no padding bytes */
    Oid            srctype;        /* source type for cast */
    Oid            dsttype;        /* destination type for cast */
    int32        srctypmod;        /* source typmod for cast */
    int32        dsttypmod;        /* destination typmod for cast */
} plpgsql_CastHashKey;

typedef struct                    /* cast_hash table entry */
{
    plpgsql_CastHashKey key;    /* hash key --- MUST BE FIRST */
    Expr       *cast_expr;        /* cast expression, or NULL if no-op cast */
    /* ExprState is valid only when cast_lxid matches current LXID */
    ExprState  *cast_exprstate; /* expression's eval tree */
    bool        cast_in_use;    /* true while we're executing eval tree */
    LocalTransactionId cast_lxid;
} plpgsql_CastHashEntry;

static MemoryContext shared_cast_context = NULL;
static HTAB *shared_cast_hash = NULL;

/************************************************************
 * Local function forward declarations
 ************************************************************/
static void plpgsql_exec_error_callback(void *arg);
static PLpgSQL_datum *copy_plpgsql_datum(PLpgSQL_datum *datum);
static MemoryContext get_stmt_mcontext(PLpgSQL_execstate *estate);
static void push_stmt_mcontext(PLpgSQL_execstate *estate);
static void pop_stmt_mcontext(PLpgSQL_execstate *estate);

static int exec_stmt_block(PLpgSQL_execstate *estate,
                PLpgSQL_stmt_block *block);
static int exec_stmts(PLpgSQL_execstate *estate,
           List *stmts);
static int exec_stmt(PLpgSQL_execstate *estate,
          PLpgSQL_stmt *stmt);
static int exec_stmt_assign(PLpgSQL_execstate *estate,
                 PLpgSQL_stmt_assign *stmt);
static int exec_stmt_perform(PLpgSQL_execstate *estate,
                  PLpgSQL_stmt_perform *stmt);
static int exec_stmt_getdiag(PLpgSQL_execstate *estate,
                  PLpgSQL_stmt_getdiag *stmt);
static int exec_stmt_if(PLpgSQL_execstate *estate,
             PLpgSQL_stmt_if *stmt);
static int exec_stmt_case(PLpgSQL_execstate *estate,
               PLpgSQL_stmt_case *stmt);
static int exec_stmt_loop(PLpgSQL_execstate *estate,
               PLpgSQL_stmt_loop *stmt);
static int exec_stmt_while(PLpgSQL_execstate *estate,
                PLpgSQL_stmt_while *stmt);
static int exec_stmt_fori(PLpgSQL_execstate *estate,
               PLpgSQL_stmt_fori *stmt);
static int exec_stmt_fors(PLpgSQL_execstate *estate,
               PLpgSQL_stmt_fors *stmt);
static int exec_stmt_forc(PLpgSQL_execstate *estate,
               PLpgSQL_stmt_forc *stmt);
static int exec_stmt_foreach_a(PLpgSQL_execstate *estate,
                    PLpgSQL_stmt_foreach_a *stmt);
static int exec_stmt_open(PLpgSQL_execstate *estate,
               PLpgSQL_stmt_open *stmt);
static int exec_stmt_fetch(PLpgSQL_execstate *estate,
                PLpgSQL_stmt_fetch *stmt);
static int exec_stmt_close(PLpgSQL_execstate *estate,
                PLpgSQL_stmt_close *stmt);
static int exec_stmt_exit(PLpgSQL_execstate *estate,
               PLpgSQL_stmt_exit *stmt);
static int exec_stmt_return(PLpgSQL_execstate *estate,
                 PLpgSQL_stmt_return *stmt);
static int exec_stmt_return_next(PLpgSQL_execstate *estate,
                      PLpgSQL_stmt_return_next *stmt);
static int exec_stmt_return_query(PLpgSQL_execstate *estate,
                       PLpgSQL_stmt_return_query *stmt);
static int exec_stmt_raise(PLpgSQL_execstate *estate,
                PLpgSQL_stmt_raise *stmt);
static int exec_stmt_assert(PLpgSQL_execstate *estate,
                 PLpgSQL_stmt_assert *stmt);
static int exec_stmt_execsql(PLpgSQL_execstate *estate,
                  PLpgSQL_stmt_execsql *stmt);
static int exec_stmt_dynexecute(PLpgSQL_execstate *estate,
                     PLpgSQL_stmt_dynexecute *stmt);
static int exec_stmt_dynfors(PLpgSQL_execstate *estate,
                  PLpgSQL_stmt_dynfors *stmt);

static void plpgsql_estate_setup(PLpgSQL_execstate *estate,
                     PLpgSQL_function *func,
                     ReturnSetInfo *rsi,
                     EState *simple_eval_estate);
static void exec_eval_cleanup(PLpgSQL_execstate *estate);

static void exec_prepare_plan(PLpgSQL_execstate *estate,
                  PLpgSQL_expr *expr, int cursorOptions);
static bool exec_simple_check_node(Node *node);
static void exec_simple_check_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr);
static void exec_simple_recheck_plan(PLpgSQL_expr *expr, CachedPlan *cplan);
static void exec_check_rw_parameter(PLpgSQL_expr *expr, int target_dno);
static bool contains_target_param(Node *node, int *target_dno);
static bool exec_eval_simple_expr(PLpgSQL_execstate *estate,
                      PLpgSQL_expr *expr,
                      Datum *result,
                      bool *isNull,
                      Oid *rettype,
                      int32 *rettypmod);

static void exec_assign_expr(PLpgSQL_execstate *estate,
                 PLpgSQL_datum *target,
                 PLpgSQL_expr *expr);
static void exec_assign_c_string(PLpgSQL_execstate *estate,
                     PLpgSQL_datum *target,
                     const char *str);
static void exec_assign_value(PLpgSQL_execstate *estate,
                  PLpgSQL_datum *target,
                  Datum value, bool isNull,
                  Oid valtype, int32 valtypmod);
static void exec_eval_datum(PLpgSQL_execstate *estate,
                PLpgSQL_datum *datum,
                Oid *typeid,
                int32 *typetypmod,
                Datum *value,
                bool *isnull);
static int exec_eval_integer(PLpgSQL_execstate *estate,
                  PLpgSQL_expr *expr,
                  bool *isNull);
static bool exec_eval_boolean(PLpgSQL_execstate *estate,
                  PLpgSQL_expr *expr,
                  bool *isNull);
static Datum exec_eval_expr(PLpgSQL_execstate *estate,
               PLpgSQL_expr *expr,
               bool *isNull,
               Oid *rettype,
               int32 *rettypmod);
static int exec_run_select(PLpgSQL_execstate *estate,
                PLpgSQL_expr *expr, long maxtuples, Portal *portalP);
static int exec_for_query(PLpgSQL_execstate *estate, PLpgSQL_stmt_forq *stmt,
               Portal portal, bool prefetch_ok);
static ParamListInfo setup_param_list(PLpgSQL_execstate *estate,
                 PLpgSQL_expr *expr);
static ParamListInfo setup_unshared_param_list(PLpgSQL_execstate *estate,
                          PLpgSQL_expr *expr);
static void plpgsql_param_fetch(ParamListInfo params, int paramid);
static void exec_move_row(PLpgSQL_execstate *estate,
              PLpgSQL_rec *rec,
              PLpgSQL_row *row,
              HeapTuple tup, TupleDesc tupdesc);
static HeapTuple make_tuple_from_row(PLpgSQL_execstate *estate,
                    PLpgSQL_row *row,
                    TupleDesc tupdesc);
static HeapTuple get_tuple_from_datum(Datum value);
static TupleDesc get_tupdesc_from_datum(Datum value);
static void exec_move_row_from_datum(PLpgSQL_execstate *estate,
                         PLpgSQL_rec *rec,
                         PLpgSQL_row *row,
                         Datum value);
static char *convert_value_to_string(PLpgSQL_execstate *estate,
                        Datum value, Oid valtype);
static Datum exec_cast_value(PLpgSQL_execstate *estate,
                Datum value, bool *isnull,
                Oid valtype, int32 valtypmod,
                Oid reqtype, int32 reqtypmod);
static plpgsql_CastHashEntry *get_cast_hashentry(PLpgSQL_execstate *estate,
                   Oid srctype, int32 srctypmod,
                   Oid dsttype, int32 dsttypmod);
static void exec_init_tuple_store(PLpgSQL_execstate *estate);
static void exec_set_found(PLpgSQL_execstate *estate, bool state);
static void plpgsql_create_econtext(PLpgSQL_execstate *estate);
static void plpgsql_destroy_econtext(PLpgSQL_execstate *estate);
static void assign_simple_var(PLpgSQL_execstate *estate, PLpgSQL_var *var,
                  Datum newvalue, bool isnull, bool freeable);
static void assign_text_var(PLpgSQL_execstate *estate, PLpgSQL_var *var,
                const char *str);
static PreparedParamsData *exec_eval_using_params(PLpgSQL_execstate *estate,
                       List *params);
static Portal exec_dynquery_with_params(PLpgSQL_execstate *estate,
                          PLpgSQL_expr *dynquery, List *params,
                          const char *portalname, int cursorOptions);
static char *format_expr_params(PLpgSQL_execstate *estate,
                   const PLpgSQL_expr *expr);
static char *format_preparedparamsdata(PLpgSQL_execstate *estate,
                          const PreparedParamsData *ppd);


/* ----------
 * plpgsql_exec_function    Called by the call handler for
 *                function execution.
 *
 * This is also used to execute inline code blocks (DO blocks).  The only
 * difference that this code is aware of is that for a DO block, we want
 * to use a private simple_eval_estate, which is created and passed in by
 * the caller.  For regular functions, pass NULL, which implies using
 * shared_simple_eval_estate.  (When using a private simple_eval_estate,
 * we must also use a private cast hashtable, but that's taken care of
 * within plpgsql_estate_setup.)
 * ----------
 */
Datum
plpgsql_exec_function(PLpgSQL_function *func, FunctionCallInfo fcinfo,
                      EState *simple_eval_estate)
{// #lizard forgives
    PLpgSQL_execstate estate;
    ErrorContextCallback plerrcontext;
    int            i;
    int            rc;

#ifdef __OPENTENBASE__
    SetEnterPlpgsqlFunc();
    SetTopXactNeedBeginTxn();
    if (PlpgsqlDebugPrint)
    {
        elog(LOG, "[PLPGSQL] plpgsql_exec_function begin g_in_plpgsql_exec_fun:%d", g_in_plpgsql_exec_fun);
    }
#endif

    /*
     * Setup the execution state
     */
    plpgsql_estate_setup(&estate, func, (ReturnSetInfo *) fcinfo->resultinfo,
                         simple_eval_estate);

    /*
     * Setup error traceback support for ereport()
     */
    plerrcontext.callback = plpgsql_exec_error_callback;
    plerrcontext.arg = &estate;
    plerrcontext.previous = error_context_stack;
    error_context_stack = &plerrcontext;

    /*
     * Make local execution copies of all the datums
     */
    estate.err_text = gettext_noop("during initialization of execution state");
    for (i = 0; i < estate.ndatums; i++)
        estate.datums[i] = copy_plpgsql_datum(func->datums[i]);

    /*
     * Store the actual call argument values into the appropriate variables
     */
    estate.err_text = gettext_noop("while storing call arguments into local variables");
    for (i = 0; i < func->fn_nargs; i++)
    {
        int            n = func->fn_argvarnos[i];

        switch (estate.datums[n]->dtype)
        {
            case PLPGSQL_DTYPE_VAR:
                {
                    PLpgSQL_var *var = (PLpgSQL_var *) estate.datums[n];

                    assign_simple_var(&estate, var,
                                      fcinfo->arg[i],
                                      fcinfo->argnull[i],
                                      false);

                    /*
                     * Force any array-valued parameter to be stored in
                     * expanded form in our local variable, in hopes of
                     * improving efficiency of uses of the variable.  (This is
                     * a hack, really: why only arrays? Need more thought
                     * about which cases are likely to win.  See also
                     * typisarray-specific heuristic in exec_assign_value.)
                     *
                     * Special cases: If passed a R/W expanded pointer, assume
                     * we can commandeer the object rather than having to copy
                     * it.  If passed a R/O expanded pointer, just keep it as
                     * the value of the variable for the moment.  (We'll force
                     * it to R/W if the variable gets modified, but that may
                     * very well never happen.)
                     */
                    if (!var->isnull && var->datatype->typisarray)
                    {
                        if (VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(var->value)))
                        {
                            /* take ownership of R/W object */
                            assign_simple_var(&estate, var,
                                              TransferExpandedObject(var->value,
                                                                     CurrentMemoryContext),
                                              false,
                                              true);
                        }
                        else if (VARATT_IS_EXTERNAL_EXPANDED_RO(DatumGetPointer(var->value)))
                        {
                            /* R/O pointer, keep it as-is until assigned to */
                        }
                        else
                        {
                            /* flat array, so force to expanded form */
                            assign_simple_var(&estate, var,
                                              expand_array(var->value,
                                                           CurrentMemoryContext,
                                                           NULL),
                                              false,
                                              true);
                        }
                    }
                }
                break;

            case PLPGSQL_DTYPE_ROW:
                {
                    PLpgSQL_row *row = (PLpgSQL_row *) estate.datums[n];

                    if (!fcinfo->argnull[i])
                    {
                        /* Assign row value from composite datum */
                        exec_move_row_from_datum(&estate, NULL, row,
                                                 fcinfo->arg[i]);
                    }
                    else
                    {
                        /* If arg is null, treat it as an empty row */
                        exec_move_row(&estate, NULL, row, NULL, NULL);
                    }
                    /* clean up after exec_move_row() */
                    exec_eval_cleanup(&estate);
                }
                break;

            default:
                elog(ERROR, "unrecognized dtype: %d", func->datums[i]->dtype);
        }
    }

    estate.err_text = gettext_noop("during function entry");

    /*
     * Set the magic variable FOUND to false
     */
    exec_set_found(&estate, false);

    /*
     * Let the instrumentation plugin peek at this function
     */
    if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_beg)
        ((*plpgsql_plugin_ptr)->func_beg) (&estate, func);

    /*
     * Now call the toplevel block of statements
     */
    estate.err_text = NULL;
    estate.err_stmt = (PLpgSQL_stmt *) (func->action);
    rc = exec_stmt_block(&estate, func->action);
    if (rc != PLPGSQL_RC_RETURN)
    {
        estate.err_stmt = NULL;
        estate.err_text = NULL;
        ereport(ERROR,
                (errcode(ERRCODE_S_R_E_FUNCTION_EXECUTED_NO_RETURN_STATEMENT),
                 errmsg("control reached end of function without RETURN")));
    }

    /*
     * We got a return value - process it
     */
    estate.err_stmt = NULL;
    estate.err_text = gettext_noop("while casting return value to function's return type");

    fcinfo->isnull = estate.retisnull;

    if (estate.retisset)
    {
        ReturnSetInfo *rsi = estate.rsi;

        /* Check caller can handle a set result */
        if (!rsi || !IsA(rsi, ReturnSetInfo) ||
            (rsi->allowedModes & SFRM_Materialize) == 0)
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("set-valued function called in context that cannot accept a set")));
        rsi->returnMode = SFRM_Materialize;

        /* If we produced any tuples, send back the result */
        if (estate.tuple_store)
        {
            rsi->setResult = estate.tuple_store;
            if (estate.rettupdesc)
            {
                MemoryContext oldcxt;

                oldcxt = MemoryContextSwitchTo(estate.tuple_store_cxt);
                rsi->setDesc = CreateTupleDescCopy(estate.rettupdesc);
                MemoryContextSwitchTo(oldcxt);
            }
        }
        estate.retval = (Datum) 0;
        fcinfo->isnull = true;
    }
    else if (!estate.retisnull)
    {
        if (estate.retistuple)
        {
            /*
             * We have to check that the returned tuple actually matches the
             * expected result type.  XXX would be better to cache the tupdesc
             * instead of repeating get_call_result_type()
             */
            HeapTuple    rettup = (HeapTuple) DatumGetPointer(estate.retval);
            TupleDesc    tupdesc;
            TupleConversionMap *tupmap;

            switch (get_call_result_type(fcinfo, NULL, &tupdesc))
            {
                case TYPEFUNC_COMPOSITE:
                    /* got the expected result rowtype, now check it */
                    tupmap = convert_tuples_by_position(estate.rettupdesc,
                                                        tupdesc,
                                                        gettext_noop("returned record type does not match expected record type"));
                    /* it might need conversion */
                    if (tupmap)
                        rettup = do_convert_tuple(rettup, tupmap, NULL);
                    /* no need to free map, we're about to return anyway */
                    break;
                case TYPEFUNC_RECORD:

                    /*
                     * Failed to determine actual type of RECORD.  We could
                     * raise an error here, but what this means in practice is
                     * that the caller is expecting any old generic rowtype,
                     * so we don't really need to be restrictive. Pass back
                     * the generated result type, instead.
                     */
                    tupdesc = estate.rettupdesc;
                    if (tupdesc == NULL)    /* shouldn't happen */
                        elog(ERROR, "return type must be a row type");
                    break;
                default:
                    /* shouldn't get here if retistuple is true ... */
                    elog(ERROR, "return type must be a row type");
                    break;
            }

            /*
             * Copy tuple to upper executor memory, as a tuple Datum. Make
             * sure it is labeled with the caller-supplied tuple type.
             */
            estate.retval = PointerGetDatum(SPI_returntuple(rettup, tupdesc));
        }
        else
        {
            /* Cast value to proper type */
            estate.retval = exec_cast_value(&estate,
                                            estate.retval,
                                            &fcinfo->isnull,
                                            estate.rettype,
                                            -1,
                                            func->fn_rettype,
                                            -1);

            /*
             * If the function's return type isn't by value, copy the value
             * into upper executor memory context.  However, if we have a R/W
             * expanded datum, we can just transfer its ownership out to the
             * upper executor context.
             */
            if (!fcinfo->isnull && !func->fn_retbyval)
                estate.retval = SPI_datumTransfer(estate.retval,
                                                  false,
                                                  func->fn_rettyplen);
        }
    }

    estate.err_text = gettext_noop("during function exit");

    /*
     * Let the instrumentation plugin peek at this function
     */
    if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_end)
        ((*plpgsql_plugin_ptr)->func_end) (&estate, func);

    /* Clean up any leftover temporary memory */
    plpgsql_destroy_econtext(&estate);
    exec_eval_cleanup(&estate);
    /* stmt_mcontext will be destroyed when function's main context is */

    /*
     * Pop the error context stack
     */
    error_context_stack = plerrcontext.previous;

    /*
     * Return the function's result
     */

#ifdef __OPENTENBASE__
    SetExitPlpgsqlFunc();
    if (PlpgsqlDebugPrint)
    {
        elog(LOG, "[PLPGSQL] plpgsql_exec_function end g_in_plpgsql_exec_fun:%d", g_in_plpgsql_exec_fun);
    }
#endif
    
    return estate.retval;
}


/* ----------
 * plpgsql_exec_trigger        Called by the call handler for
 *                trigger execution.
 * ----------
 */
HeapTuple
plpgsql_exec_trigger(PLpgSQL_function *func,
                     TriggerData *trigdata)
{// #lizard forgives
    PLpgSQL_execstate estate;
    ErrorContextCallback plerrcontext;
    int            i;
    int            rc;
    PLpgSQL_var *var;
    PLpgSQL_rec *rec_new,
               *rec_old;
    HeapTuple    rettup;

    /*
     * Setup the execution state
     */
    plpgsql_estate_setup(&estate, func, NULL, NULL);

    /*
     * Setup error traceback support for ereport()
     */
    plerrcontext.callback = plpgsql_exec_error_callback;
    plerrcontext.arg = &estate;
    plerrcontext.previous = error_context_stack;
    error_context_stack = &plerrcontext;

    /*
     * Make local execution copies of all the datums
     */
    estate.err_text = gettext_noop("during initialization of execution state");
    for (i = 0; i < estate.ndatums; i++)
        estate.datums[i] = copy_plpgsql_datum(func->datums[i]);

    /*
     * Put the OLD and NEW tuples into record variables
     *
     * We make the tupdescs available in both records even though only one may
     * have a value.  This allows parsing of record references to succeed in
     * functions that are used for multiple trigger types.  For example, we
     * might have a test like "if (TG_OP = 'INSERT' and NEW.foo = 'xyz')",
     * which should parse regardless of the current trigger type.
     */
    rec_new = (PLpgSQL_rec *) (estate.datums[func->new_varno]);
    rec_new->freetup = false;
    rec_new->tupdesc = trigdata->tg_relation->rd_att;
    rec_new->freetupdesc = false;
    rec_old = (PLpgSQL_rec *) (estate.datums[func->old_varno]);
    rec_old->freetup = false;
    rec_old->tupdesc = trigdata->tg_relation->rd_att;
    rec_old->freetupdesc = false;

    if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
    {
        /*
         * Per-statement triggers don't use OLD/NEW variables
         */
        rec_new->tup = NULL;
        rec_old->tup = NULL;
    }
    else if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
    {
        rec_new->tup = trigdata->tg_trigtuple;
        rec_old->tup = NULL;
    }
    else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
    {
        rec_new->tup = trigdata->tg_newtuple;
        rec_old->tup = trigdata->tg_trigtuple;
    }
    else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
    {
        rec_new->tup = NULL;
        rec_old->tup = trigdata->tg_trigtuple;
    }
    else
        elog(ERROR, "unrecognized trigger action: not INSERT, DELETE, or UPDATE");

    /* Make transition tables visible to this SPI connection */
    rc = SPI_register_trigger_data(trigdata);
    Assert(rc >= 0);

    /*
     * Assign the special tg_ variables
     */

    var = (PLpgSQL_var *) (estate.datums[func->tg_op_varno]);
    if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
        assign_text_var(&estate, var, "INSERT");
    else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
        assign_text_var(&estate, var, "UPDATE");
    else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
        assign_text_var(&estate, var, "DELETE");
    else if (TRIGGER_FIRED_BY_TRUNCATE(trigdata->tg_event))
        assign_text_var(&estate, var, "TRUNCATE");
    else
        elog(ERROR, "unrecognized trigger action: not INSERT, DELETE, UPDATE, or TRUNCATE");

    var = (PLpgSQL_var *) (estate.datums[func->tg_name_varno]);
    assign_simple_var(&estate, var,
                      DirectFunctionCall1(namein,
                                          CStringGetDatum(trigdata->tg_trigger->tgname)),
                      false, true);

    var = (PLpgSQL_var *) (estate.datums[func->tg_when_varno]);
    if (TRIGGER_FIRED_BEFORE(trigdata->tg_event))
        assign_text_var(&estate, var, "BEFORE");
    else if (TRIGGER_FIRED_AFTER(trigdata->tg_event))
        assign_text_var(&estate, var, "AFTER");
    else if (TRIGGER_FIRED_INSTEAD(trigdata->tg_event))
        assign_text_var(&estate, var, "INSTEAD OF");
    else
        elog(ERROR, "unrecognized trigger execution time: not BEFORE, AFTER, or INSTEAD OF");

    var = (PLpgSQL_var *) (estate.datums[func->tg_level_varno]);
    if (TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
        assign_text_var(&estate, var, "ROW");
    else if (TRIGGER_FIRED_FOR_STATEMENT(trigdata->tg_event))
        assign_text_var(&estate, var, "STATEMENT");
    else
        elog(ERROR, "unrecognized trigger event type: not ROW or STATEMENT");

    var = (PLpgSQL_var *) (estate.datums[func->tg_relid_varno]);
    assign_simple_var(&estate, var,
                      ObjectIdGetDatum(trigdata->tg_relation->rd_id),
                      false, false);

    var = (PLpgSQL_var *) (estate.datums[func->tg_relname_varno]);
    assign_simple_var(&estate, var,
                      DirectFunctionCall1(namein,
                                          CStringGetDatum(RelationGetRelationName(trigdata->tg_relation))),
                      false, true);

    var = (PLpgSQL_var *) (estate.datums[func->tg_table_name_varno]);
    assign_simple_var(&estate, var,
                      DirectFunctionCall1(namein,
                                          CStringGetDatum(RelationGetRelationName(trigdata->tg_relation))),
                      false, true);

    var = (PLpgSQL_var *) (estate.datums[func->tg_table_schema_varno]);
    assign_simple_var(&estate, var,
                      DirectFunctionCall1(namein,
                                          CStringGetDatum(get_namespace_name(
                                                                             RelationGetNamespace(
                                                                                                  trigdata->tg_relation)))),
                      false, true);

    var = (PLpgSQL_var *) (estate.datums[func->tg_nargs_varno]);
    assign_simple_var(&estate, var,
                      Int16GetDatum(trigdata->tg_trigger->tgnargs),
                      false, false);

    var = (PLpgSQL_var *) (estate.datums[func->tg_argv_varno]);
    if (trigdata->tg_trigger->tgnargs > 0)
    {
        /*
         * For historical reasons, tg_argv[] subscripts start at zero not one.
         * So we can't use construct_array().
         */
        int            nelems = trigdata->tg_trigger->tgnargs;
        Datum       *elems;
        int            dims[1];
        int            lbs[1];

        elems = palloc(sizeof(Datum) * nelems);
        for (i = 0; i < nelems; i++)
            elems[i] = CStringGetTextDatum(trigdata->tg_trigger->tgargs[i]);
        dims[0] = nelems;
        lbs[0] = 0;

        assign_simple_var(&estate, var,
                          PointerGetDatum(construct_md_array(elems, NULL,
                                                             1, dims, lbs,
                                                             TEXTOID,
                                                             -1, false, 'i')),
                          false, true);
    }
    else
    {
        assign_simple_var(&estate, var, (Datum) 0, true, false);
    }

    estate.err_text = gettext_noop("during function entry");

    /*
     * Set the magic variable FOUND to false
     */
    exec_set_found(&estate, false);

    /*
     * Let the instrumentation plugin peek at this function
     */
    if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_beg)
        ((*plpgsql_plugin_ptr)->func_beg) (&estate, func);

    /*
     * Now call the toplevel block of statements
     */
    estate.err_text = NULL;
    estate.err_stmt = (PLpgSQL_stmt *) (func->action);
    rc = exec_stmt_block(&estate, func->action);
    if (rc != PLPGSQL_RC_RETURN)
    {
        estate.err_stmt = NULL;
        estate.err_text = NULL;
        ereport(ERROR,
                (errcode(ERRCODE_S_R_E_FUNCTION_EXECUTED_NO_RETURN_STATEMENT),
                 errmsg("control reached end of trigger procedure without RETURN")));
    }

    estate.err_stmt = NULL;
    estate.err_text = gettext_noop("during function exit");

    if (estate.retisset)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("trigger procedure cannot return a set")));

    /*
     * Check that the returned tuple structure has the same attributes, the
     * relation that fired the trigger has. A per-statement trigger always
     * needs to return NULL, so we ignore any return value the function itself
     * produces (XXX: is this a good idea?)
     *
     * XXX This way it is possible, that the trigger returns a tuple where
     * attributes don't have the correct atttypmod's length. It's up to the
     * trigger's programmer to ensure that this doesn't happen. Jan
     */
    if (estate.retisnull || !TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
        rettup = NULL;
    else
    {
        TupleConversionMap *tupmap;

        rettup = (HeapTuple) DatumGetPointer(estate.retval);
        /* check rowtype compatibility */
        tupmap = convert_tuples_by_position(estate.rettupdesc,
                                            trigdata->tg_relation->rd_att,
                                            gettext_noop("returned row structure does not match the structure of the triggering table"));
        /* it might need conversion */
        if (tupmap)
            rettup = do_convert_tuple(rettup, tupmap, trigdata->tg_relation);
        /* no need to free map, we're about to return anyway */

        /* Copy tuple to upper executor memory */
        rettup = SPI_copytuple(rettup);
    }

    /*
     * Let the instrumentation plugin peek at this function
     */
    if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_end)
        ((*plpgsql_plugin_ptr)->func_end) (&estate, func);

    /* Clean up any leftover temporary memory */
    plpgsql_destroy_econtext(&estate);
    exec_eval_cleanup(&estate);
    /* stmt_mcontext will be destroyed when function's main context is */

    /*
     * Pop the error context stack
     */
    error_context_stack = plerrcontext.previous;

    /*
     * Return the trigger's result
     */
    return rettup;
}

/* ----------
 * plpgsql_exec_event_trigger        Called by the call handler for
 *                event trigger execution.
 * ----------
 */
void
plpgsql_exec_event_trigger(PLpgSQL_function *func, EventTriggerData *trigdata)
{
    PLpgSQL_execstate estate;
    ErrorContextCallback plerrcontext;
    int            i;
    int            rc;
    PLpgSQL_var *var;

    /*
     * Setup the execution state
     */
    plpgsql_estate_setup(&estate, func, NULL, NULL);

    /*
     * Setup error traceback support for ereport()
     */
    plerrcontext.callback = plpgsql_exec_error_callback;
    plerrcontext.arg = &estate;
    plerrcontext.previous = error_context_stack;
    error_context_stack = &plerrcontext;

    /*
     * Make local execution copies of all the datums
     */
    estate.err_text = gettext_noop("during initialization of execution state");
    for (i = 0; i < estate.ndatums; i++)
        estate.datums[i] = copy_plpgsql_datum(func->datums[i]);

    /*
     * Assign the special tg_ variables
     */
    var = (PLpgSQL_var *) (estate.datums[func->tg_event_varno]);
    assign_text_var(&estate, var, trigdata->event);

    var = (PLpgSQL_var *) (estate.datums[func->tg_tag_varno]);
    assign_text_var(&estate, var, trigdata->tag);

    /*
     * Let the instrumentation plugin peek at this function
     */
    if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_beg)
        ((*plpgsql_plugin_ptr)->func_beg) (&estate, func);

    /*
     * Now call the toplevel block of statements
     */
    estate.err_text = NULL;
    estate.err_stmt = (PLpgSQL_stmt *) (func->action);
    rc = exec_stmt_block(&estate, func->action);
    if (rc != PLPGSQL_RC_RETURN)
    {
        estate.err_stmt = NULL;
        estate.err_text = NULL;
        ereport(ERROR,
                (errcode(ERRCODE_S_R_E_FUNCTION_EXECUTED_NO_RETURN_STATEMENT),
                 errmsg("control reached end of trigger procedure without RETURN")));
    }

    estate.err_stmt = NULL;
    estate.err_text = gettext_noop("during function exit");

    /*
     * Let the instrumentation plugin peek at this function
     */
    if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_end)
        ((*plpgsql_plugin_ptr)->func_end) (&estate, func);

    /* Clean up any leftover temporary memory */
    plpgsql_destroy_econtext(&estate);
    exec_eval_cleanup(&estate);
    /* stmt_mcontext will be destroyed when function's main context is */

    /*
     * Pop the error context stack
     */
    error_context_stack = plerrcontext.previous;

    return;
}

/*
 * error context callback to let us supply a call-stack traceback
 */
static void
plpgsql_exec_error_callback(void *arg)
{
    PLpgSQL_execstate *estate = (PLpgSQL_execstate *) arg;

    if (estate->err_text != NULL)
    {
        /*
         * We don't expend the cycles to run gettext() on err_text unless we
         * actually need it.  Therefore, places that set up err_text should
         * use gettext_noop() to ensure the strings get recorded in the
         * message dictionary.
         *
         * If both err_text and err_stmt are set, use the err_text as
         * description, but report the err_stmt's line number.  When err_stmt
         * is not set, we're in function entry/exit, or some such place not
         * attached to a specific line number.
         */
        if (estate->err_stmt != NULL)
        {
            /*
             * translator: last %s is a phrase such as "during statement block
             * local variable initialization"
             */
            errcontext("PL/pgSQL function %s line %d %s",
                       estate->func->fn_signature,
                       estate->err_stmt->lineno,
                       _(estate->err_text));
        }
        else
        {
            /*
             * translator: last %s is a phrase such as "while storing call
             * arguments into local variables"
             */
            errcontext("PL/pgSQL function %s %s",
                       estate->func->fn_signature,
                       _(estate->err_text));
        }
    }
    else if (estate->err_stmt != NULL)
    {
        /* translator: last %s is a plpgsql statement type name */
        errcontext("PL/pgSQL function %s line %d at %s",
                   estate->func->fn_signature,
                   estate->err_stmt->lineno,
                   plpgsql_stmt_typename(estate->err_stmt));
    }
    else
        errcontext("PL/pgSQL function %s",
                   estate->func->fn_signature);
}


/* ----------
 * Support function for initializing local execution variables
 * ----------
 */
static PLpgSQL_datum *
copy_plpgsql_datum(PLpgSQL_datum *datum)
{
    PLpgSQL_datum *result;

    switch (datum->dtype)
    {
        case PLPGSQL_DTYPE_VAR:
            {
                PLpgSQL_var *new = palloc(sizeof(PLpgSQL_var));

                memcpy(new, datum, sizeof(PLpgSQL_var));
                /* should be preset to null/non-freeable */
                Assert(new->isnull);
                Assert(!new->freeval);

                result = (PLpgSQL_datum *) new;
            }
            break;

        case PLPGSQL_DTYPE_REC:
            {
                PLpgSQL_rec *new = palloc(sizeof(PLpgSQL_rec));

                memcpy(new, datum, sizeof(PLpgSQL_rec));
                /* should be preset to null/non-freeable */
                Assert(new->tup == NULL);
                Assert(new->tupdesc == NULL);
                Assert(!new->freetup);
                Assert(!new->freetupdesc);

                result = (PLpgSQL_datum *) new;
            }
            break;

        case PLPGSQL_DTYPE_ROW:
        case PLPGSQL_DTYPE_RECFIELD:
        case PLPGSQL_DTYPE_ARRAYELEM:

            /*
             * These datum records are read-only at runtime, so no need to
             * copy them (well, ARRAYELEM contains some cached type data, but
             * we'd just as soon centralize the caching anyway)
             */
            result = datum;
            break;

        default:
            elog(ERROR, "unrecognized dtype: %d", datum->dtype);
            result = NULL;        /* keep compiler quiet */
            break;
    }

    return result;
}

/*
 * Create a memory context for statement-lifespan variables, if we don't
 * have one already.  It will be a child of stmt_mcontext_parent, which is
 * either the function's main context or a pushed-down outer stmt_mcontext.
 */
static MemoryContext
get_stmt_mcontext(PLpgSQL_execstate *estate)
{
    if (estate->stmt_mcontext == NULL)
    {
        estate->stmt_mcontext =
            AllocSetContextCreate(estate->stmt_mcontext_parent,
                                  "PLpgSQL per-statement data",
                                  ALLOCSET_DEFAULT_SIZES);
    }
    return estate->stmt_mcontext;
}

/*
 * Push down the current stmt_mcontext so that called statements won't use it.
 * This is needed by statements that have statement-lifespan data and need to
 * preserve it across some inner statements.  The caller should eventually do
 * pop_stmt_mcontext().
 */
static void
push_stmt_mcontext(PLpgSQL_execstate *estate)
{
    /* Should have done get_stmt_mcontext() first */
    Assert(estate->stmt_mcontext != NULL);
    /* Assert we've not messed up the stack linkage */
    Assert(MemoryContextGetParent(estate->stmt_mcontext) == estate->stmt_mcontext_parent);
    /* Push it down to become the parent of any nested stmt mcontext */
    estate->stmt_mcontext_parent = estate->stmt_mcontext;
    /* And make it not available for use directly */
    estate->stmt_mcontext = NULL;
}

/*
 * Undo push_stmt_mcontext().  We assume this is done just before or after
 * resetting the caller's stmt_mcontext; since that action will also delete
 * any child contexts, there's no need to explicitly delete whatever context
 * might currently be estate->stmt_mcontext.
 */
static void
pop_stmt_mcontext(PLpgSQL_execstate *estate)
{
    /* We need only pop the stack */
    estate->stmt_mcontext = estate->stmt_mcontext_parent;
    estate->stmt_mcontext_parent = MemoryContextGetParent(estate->stmt_mcontext);
}


/*
 * Subroutine for exec_stmt_block: does any condition in the condition list
 * match the current exception?
 */
static bool
exception_matches_conditions(ErrorData *edata, PLpgSQL_condition *cond)
{// #lizard forgives
    for (; cond != NULL; cond = cond->next)
    {
        int            sqlerrstate = cond->sqlerrstate;

        /*
         * OTHERS matches everything *except* query-canceled and
         * assert-failure.  If you're foolish enough, you can match those
         * explicitly.
         */
        if (sqlerrstate == 0)
        {
            if (edata->sqlerrcode != ERRCODE_QUERY_CANCELED &&
                edata->sqlerrcode != ERRCODE_ASSERT_FAILURE)
                return true;
        }
        /* Exact match? */
        else if (edata->sqlerrcode == sqlerrstate)
            return true;
        /* Category match? */
        else if (ERRCODE_IS_CATEGORY(sqlerrstate) &&
                 ERRCODE_TO_CATEGORY(edata->sqlerrcode) == sqlerrstate)
            return true;
    }
    return false;
}


/* ----------
 * exec_stmt_block            Execute a block of statements
 * ----------
 */
static int
exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block)
{// #lizard forgives
    volatile int rc = -1;
    int            i;
    int            n;

    /*
     * First initialize all variables declared in this block
     */
    estate->err_text = gettext_noop("during statement block local variable initialization");

    for (i = 0; i < block->n_initvars; i++)
    {
        n = block->initvarnos[i];

        switch (estate->datums[n]->dtype)
        {
            case PLPGSQL_DTYPE_VAR:
                {
                    PLpgSQL_var *var = (PLpgSQL_var *) (estate->datums[n]);

                    /*
                     * Free any old value, in case re-entering block, and
                     * initialize to NULL
                     */
                    assign_simple_var(estate, var, (Datum) 0, true, false);

                    if (var->default_val == NULL)
                    {
                        /*
                         * If needed, give the datatype a chance to reject
                         * NULLs, by assigning a NULL to the variable. We
                         * claim the value is of type UNKNOWN, not the var's
                         * datatype, else coercion will be skipped. (Do this
                         * before the notnull check to be consistent with
                         * exec_assign_value.)
                         */
                        if (var->datatype->typtype == TYPTYPE_DOMAIN)
                            exec_assign_value(estate,
                                              (PLpgSQL_datum *) var,
                                              (Datum) 0,
                                              true,
                                              UNKNOWNOID,
                                              -1);

                        if (var->notnull)
                            ereport(ERROR,
                                    (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                                     errmsg("variable \"%s\" declared NOT NULL cannot default to NULL",
                                            var->refname)));
                    }
                    else
                    {
                        exec_assign_expr(estate, (PLpgSQL_datum *) var,
                                         var->default_val);
                    }
                }
                break;

            case PLPGSQL_DTYPE_REC:
                {
                    PLpgSQL_rec *rec = (PLpgSQL_rec *) (estate->datums[n]);

                    if (rec->freetup)
                    {
                        heap_freetuple(rec->tup);
                        rec->freetup = false;
                    }
                    if (rec->freetupdesc)
                    {
                        FreeTupleDesc(rec->tupdesc);
                        rec->freetupdesc = false;
                    }
                    rec->tup = NULL;
                    rec->tupdesc = NULL;
                }
                break;

            case PLPGSQL_DTYPE_RECFIELD:
            case PLPGSQL_DTYPE_ARRAYELEM:
                break;

            default:
                elog(ERROR, "unrecognized dtype: %d",
                     estate->datums[n]->dtype);
        }
    }

    if (block->exceptions)
    {
        /*
         * Execute the statements in the block's body inside a sub-transaction
         */
        MemoryContext oldcontext = CurrentMemoryContext;
        ResourceOwner oldowner = CurrentResourceOwner;
        ExprContext *old_eval_econtext = estate->eval_econtext;
        ErrorData  *save_cur_error = estate->cur_error;
        MemoryContext stmt_mcontext;

        estate->err_text = gettext_noop("during statement block entry");

        /*
         * We will need a stmt_mcontext to hold the error data if an error
         * occurs.  It seems best to force it to exist before entering the
         * subtransaction, so that we reduce the risk of out-of-memory during
         * error recovery, and because this greatly simplifies restoring the
         * stmt_mcontext stack to the correct state after an error.  We can
         * ameliorate the cost of this by allowing the called statements to
         * use this mcontext too; so we don't push it down here.
         */
        stmt_mcontext = get_stmt_mcontext(estate);

		SetEnterPlpgsqlFunc();
        BeginInternalSubTransaction(NULL);
        /* Want to run statements inside function's memory context */
        MemoryContextSwitchTo(oldcontext);

        estate->handle_exceptions = false;

        PG_TRY();
        {
            /*
             * We need to run the block's statements with a new eval_econtext
             * that belongs to the current subtransaction; if we try to use
             * the outer econtext then ExprContext shutdown callbacks will be
             * called at the wrong times.
             */
            plpgsql_create_econtext(estate);

            estate->err_text = NULL;

            /* Run the block's statements */
            rc = exec_stmts(estate, block->body);

            estate->err_text = gettext_noop("during statement block exit");

            /*
             * If the block ended with RETURN, we may need to copy the return
             * value out of the subtransaction eval_context.  This is
             * currently only needed for scalar result types --- rowtype
             * values will always exist in the function's main memory context,
             * cf. exec_stmt_return().  We can avoid a physical copy if the
             * value happens to be a R/W expanded object.
             */
            if (rc == PLPGSQL_RC_RETURN &&
                !estate->retisset &&
                !estate->retisnull &&
                estate->rettupdesc == NULL)
            {
                int16        resTypLen;
                bool        resTypByVal;

                get_typlenbyval(estate->rettype, &resTypLen, &resTypByVal);
                estate->retval = datumTransfer(estate->retval,
                                               resTypByVal, resTypLen);
            }

            /* Commit the inner transaction, return to outer xact context */
            ReleaseCurrentSubTransaction();
            MemoryContextSwitchTo(oldcontext);
            CurrentResourceOwner = oldowner;

            /* Assert that the stmt_mcontext stack is unchanged */
            Assert(stmt_mcontext == estate->stmt_mcontext);

            /*
             * Revert to outer eval_econtext.  (The inner one was
             * automatically cleaned up during subxact exit.)
             */
            estate->eval_econtext = old_eval_econtext;
        }
        PG_CATCH();
        {
            ErrorData  *edata;
            ListCell   *e;

            estate->err_text = gettext_noop("during exception cleanup");

            /* Save error info in our stmt_mcontext */
            MemoryContextSwitchTo(stmt_mcontext);
            edata = CopyErrorData();
            FlushErrorState();

			/* Mark handling exceptions */
            estate->handle_exceptions = true;

            /* Abort the inner transaction */
            RollbackAndReleaseCurrentSubTransaction();
            MemoryContextSwitchTo(oldcontext);
            CurrentResourceOwner = oldowner;

            /*
             * Set up the stmt_mcontext stack as though we had restored our
             * previous state and then done push_stmt_mcontext().  The push is
             * needed so that statements in the exception handler won't
             * clobber the error data that's in our stmt_mcontext.
             */
            estate->stmt_mcontext_parent = stmt_mcontext;
            estate->stmt_mcontext = NULL;

            /*
             * Now we can delete any nested stmt_mcontexts that might have
             * been created as children of ours.  (Note: we do not immediately
             * release any statement-lifespan data that might have been left
             * behind in stmt_mcontext itself.  We could attempt that by doing
             * a MemoryContextReset on it before collecting the error data
             * above, but it seems too risky to do any significant amount of
             * work before collecting the error.)
             */
            MemoryContextDeleteChildren(stmt_mcontext);

            /* Revert to outer eval_econtext */
            estate->eval_econtext = old_eval_econtext;

            /*
             * Must clean up the econtext too.  However, any tuple table made
             * in the subxact will have been thrown away by SPI during subxact
             * abort, so we don't need to (and mustn't try to) free the
             * eval_tuptable.
             */
            estate->eval_tuptable = NULL;
            exec_eval_cleanup(estate);

            /* Look for a matching exception handler */
            foreach(e, block->exceptions->exc_list)
            {
                PLpgSQL_exception *exception = (PLpgSQL_exception *) lfirst(e);

                if (exception_matches_conditions(edata, exception->conditions))
                {
                    /*
                     * Initialize the magic SQLSTATE and SQLERRM variables for
                     * the exception block; this also frees values from any
                     * prior use of the same exception. We needn't do this
                     * until we have found a matching exception.
                     */
                    PLpgSQL_var *state_var;
                    PLpgSQL_var *errm_var;

                    state_var = (PLpgSQL_var *)
                        estate->datums[block->exceptions->sqlstate_varno];
                    errm_var = (PLpgSQL_var *)
                        estate->datums[block->exceptions->sqlerrm_varno];

                    assign_text_var(estate, state_var,
                                    unpack_sql_state(edata->sqlerrcode));
                    assign_text_var(estate, errm_var, edata->message);

                    /*
                     * Also set up cur_error so the error data is accessible
                     * inside the handler.
                     */
                    estate->cur_error = edata;

                    estate->err_text = NULL;

                    rc = exec_stmts(estate, exception->action);

					estate->handle_exceptions = false;

                    break;
                }
            }

            /*
             * Restore previous state of cur_error, whether or not we executed
             * a handler.  This is needed in case an error got thrown from
             * some inner block's exception handler.
             */
            estate->cur_error = save_cur_error;

            /* If no match found, re-throw the error */
            if (e == NULL)
            {
                SetExitPlpgsqlFunc();
                ReThrowError(edata);
            }
			 else
				FreeErrorData(edata);

            /* Restore stmt_mcontext stack and release the error data */
            pop_stmt_mcontext(estate);
            MemoryContextReset(stmt_mcontext);
        }
        PG_END_TRY();

		SetExitPlpgsqlFunc();
        Assert(save_cur_error == estate->cur_error);
    }
    else
    {
        /*
         * Just execute the statements in the block's body
         */
        estate->err_text = NULL;

        rc = exec_stmts(estate, block->body);
    }

    estate->err_text = NULL;

    /*
     * Handle the return code.
     */
    switch (rc)
    {
        case PLPGSQL_RC_OK:
        case PLPGSQL_RC_RETURN:
        case PLPGSQL_RC_CONTINUE:
            return rc;

        case PLPGSQL_RC_EXIT:

            /*
             * This is intentionally different from the handling of RC_EXIT
             * for loops: to match a block, we require a match by label.
             */
            if (estate->exitlabel == NULL)
                return PLPGSQL_RC_EXIT;
            if (block->label == NULL)
                return PLPGSQL_RC_EXIT;
            if (strcmp(block->label, estate->exitlabel) != 0)
                return PLPGSQL_RC_EXIT;
            estate->exitlabel = NULL;
            return PLPGSQL_RC_OK;

        default:
            elog(ERROR, "unrecognized rc: %d", rc);
    }

    return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmts            Iterate over a list of statements
 *                as long as their return code is OK
 * ----------
 */
static int
exec_stmts(PLpgSQL_execstate *estate, List *stmts)
{
    ListCell   *s;

    if (stmts == NIL)
    {
        /*
         * Ensure we do a CHECK_FOR_INTERRUPTS() even though there is no
         * statement.  This prevents hangup in a tight loop if, for instance,
         * there is a LOOP construct with an empty body.
         */
        CHECK_FOR_INTERRUPTS();
        return PLPGSQL_RC_OK;
    }

    foreach(s, stmts)
    {
        PLpgSQL_stmt *stmt = (PLpgSQL_stmt *) lfirst(s);
        int            rc = exec_stmt(estate, stmt);

        if (rc != PLPGSQL_RC_OK)
            return rc;
    }

    return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmt            Distribute one statement to the statements
 *                type specific execution function.
 * ----------
 */
static int
exec_stmt(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
{// #lizard forgives
    PLpgSQL_stmt *save_estmt;
    int            rc = -1;

    save_estmt = estate->err_stmt;
    estate->err_stmt = stmt;

    /* Let the plugin know that we are about to execute this statement */
    if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->stmt_beg)
        ((*plpgsql_plugin_ptr)->stmt_beg) (estate, stmt);

    CHECK_FOR_INTERRUPTS();

    switch (stmt->cmd_type)
    {
        case PLPGSQL_STMT_BLOCK:
            rc = exec_stmt_block(estate, (PLpgSQL_stmt_block *) stmt);
            break;

        case PLPGSQL_STMT_ASSIGN:
            rc = exec_stmt_assign(estate, (PLpgSQL_stmt_assign *) stmt);
            break;

        case PLPGSQL_STMT_PERFORM:
            rc = exec_stmt_perform(estate, (PLpgSQL_stmt_perform *) stmt);
            break;

        case PLPGSQL_STMT_GETDIAG:
            rc = exec_stmt_getdiag(estate, (PLpgSQL_stmt_getdiag *) stmt);
            break;

        case PLPGSQL_STMT_IF:
            rc = exec_stmt_if(estate, (PLpgSQL_stmt_if *) stmt);
            break;

        case PLPGSQL_STMT_CASE:
            rc = exec_stmt_case(estate, (PLpgSQL_stmt_case *) stmt);
            break;

        case PLPGSQL_STMT_LOOP:
            rc = exec_stmt_loop(estate, (PLpgSQL_stmt_loop *) stmt);
            break;

        case PLPGSQL_STMT_WHILE:
            rc = exec_stmt_while(estate, (PLpgSQL_stmt_while *) stmt);
            break;

        case PLPGSQL_STMT_FORI:
            rc = exec_stmt_fori(estate, (PLpgSQL_stmt_fori *) stmt);
            break;

        case PLPGSQL_STMT_FORS:
            rc = exec_stmt_fors(estate, (PLpgSQL_stmt_fors *) stmt);
            break;

        case PLPGSQL_STMT_FORC:
            rc = exec_stmt_forc(estate, (PLpgSQL_stmt_forc *) stmt);
            break;

        case PLPGSQL_STMT_FOREACH_A:
            rc = exec_stmt_foreach_a(estate, (PLpgSQL_stmt_foreach_a *) stmt);
            break;

        case PLPGSQL_STMT_EXIT:
            rc = exec_stmt_exit(estate, (PLpgSQL_stmt_exit *) stmt);
            break;

        case PLPGSQL_STMT_RETURN:
            rc = exec_stmt_return(estate, (PLpgSQL_stmt_return *) stmt);
            break;

        case PLPGSQL_STMT_RETURN_NEXT:
            rc = exec_stmt_return_next(estate, (PLpgSQL_stmt_return_next *) stmt);
            break;

        case PLPGSQL_STMT_RETURN_QUERY:
            rc = exec_stmt_return_query(estate, (PLpgSQL_stmt_return_query *) stmt);
            break;

        case PLPGSQL_STMT_RAISE:
            rc = exec_stmt_raise(estate, (PLpgSQL_stmt_raise *) stmt);
            break;

        case PLPGSQL_STMT_ASSERT:
            rc = exec_stmt_assert(estate, (PLpgSQL_stmt_assert *) stmt);
            break;

        case PLPGSQL_STMT_EXECSQL:
            rc = exec_stmt_execsql(estate, (PLpgSQL_stmt_execsql *) stmt);
            break;

        case PLPGSQL_STMT_DYNEXECUTE:
            rc = exec_stmt_dynexecute(estate, (PLpgSQL_stmt_dynexecute *) stmt);
            break;

        case PLPGSQL_STMT_DYNFORS:
            rc = exec_stmt_dynfors(estate, (PLpgSQL_stmt_dynfors *) stmt);
            break;

        case PLPGSQL_STMT_OPEN:
            rc = exec_stmt_open(estate, (PLpgSQL_stmt_open *) stmt);
            break;

        case PLPGSQL_STMT_FETCH:
            rc = exec_stmt_fetch(estate, (PLpgSQL_stmt_fetch *) stmt);
            break;

        case PLPGSQL_STMT_CLOSE:
            rc = exec_stmt_close(estate, (PLpgSQL_stmt_close *) stmt);
            break;

        default:
            estate->err_stmt = save_estmt;
            elog(ERROR, "unrecognized cmdtype: %d", stmt->cmd_type);
    }

    /* Let the plugin know that we have finished executing this statement */
    if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->stmt_end)
        ((*plpgsql_plugin_ptr)->stmt_end) (estate, stmt);

    estate->err_stmt = save_estmt;

    return rc;
}


/* ----------
 * exec_stmt_assign            Evaluate an expression and
 *                    put the result into a variable.
 * ----------
 */
static int
exec_stmt_assign(PLpgSQL_execstate *estate, PLpgSQL_stmt_assign *stmt)
{
    Assert(stmt->varno >= 0);

    exec_assign_expr(estate, estate->datums[stmt->varno], stmt->expr);

    return PLPGSQL_RC_OK;
}

/* ----------
 * exec_stmt_perform        Evaluate query and discard result (but set
 *                            FOUND depending on whether at least one row
 *                            was returned).
 * ----------
 */
static int
exec_stmt_perform(PLpgSQL_execstate *estate, PLpgSQL_stmt_perform *stmt)
{
    PLpgSQL_expr *expr = stmt->expr;

    (void) exec_run_select(estate, expr, 0, NULL);
    exec_set_found(estate, (estate->eval_processed != 0));
    exec_eval_cleanup(estate);

    return PLPGSQL_RC_OK;
}

/* ----------
 * exec_stmt_getdiag                    Put internal PG information into
 *                                        specified variables.
 * ----------
 */
static int
exec_stmt_getdiag(PLpgSQL_execstate *estate, PLpgSQL_stmt_getdiag *stmt)
{// #lizard forgives
    ListCell   *lc;

    /*
     * GET STACKED DIAGNOSTICS is only valid inside an exception handler.
     *
     * Note: we trust the grammar to have disallowed the relevant item kinds
     * if not is_stacked, otherwise we'd dump core below.
     */
    if (stmt->is_stacked && estate->cur_error == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_STACKED_DIAGNOSTICS_ACCESSED_WITHOUT_ACTIVE_HANDLER),
                 errmsg("GET STACKED DIAGNOSTICS cannot be used outside an exception handler")));

    foreach(lc, stmt->diag_items)
    {
        PLpgSQL_diag_item *diag_item = (PLpgSQL_diag_item *) lfirst(lc);
        PLpgSQL_datum *var = estate->datums[diag_item->target];

        switch (diag_item->kind)
        {
            case PLPGSQL_GETDIAG_ROW_COUNT:
                exec_assign_value(estate, var,
                                  UInt64GetDatum(estate->eval_processed),
                                  false, INT8OID, -1);
                break;

            case PLPGSQL_GETDIAG_RESULT_OID:
                exec_assign_value(estate, var,
                                  ObjectIdGetDatum(estate->eval_lastoid),
                                  false, OIDOID, -1);
                break;

            case PLPGSQL_GETDIAG_ERROR_CONTEXT:
                exec_assign_c_string(estate, var,
                                     estate->cur_error->context);
                break;

            case PLPGSQL_GETDIAG_ERROR_DETAIL:
                exec_assign_c_string(estate, var,
                                     estate->cur_error->detail);
                break;

            case PLPGSQL_GETDIAG_ERROR_HINT:
                exec_assign_c_string(estate, var,
                                     estate->cur_error->hint);
                break;

            case PLPGSQL_GETDIAG_RETURNED_SQLSTATE:
                exec_assign_c_string(estate, var,
                                     unpack_sql_state(estate->cur_error->sqlerrcode));
                break;

            case PLPGSQL_GETDIAG_COLUMN_NAME:
                exec_assign_c_string(estate, var,
                                     estate->cur_error->column_name);
                break;

            case PLPGSQL_GETDIAG_CONSTRAINT_NAME:
                exec_assign_c_string(estate, var,
                                     estate->cur_error->constraint_name);
                break;

            case PLPGSQL_GETDIAG_DATATYPE_NAME:
                exec_assign_c_string(estate, var,
                                     estate->cur_error->datatype_name);
                break;

            case PLPGSQL_GETDIAG_MESSAGE_TEXT:
                exec_assign_c_string(estate, var,
                                     estate->cur_error->message);
                break;

            case PLPGSQL_GETDIAG_TABLE_NAME:
                exec_assign_c_string(estate, var,
                                     estate->cur_error->table_name);
                break;

            case PLPGSQL_GETDIAG_SCHEMA_NAME:
                exec_assign_c_string(estate, var,
                                     estate->cur_error->schema_name);
                break;

            case PLPGSQL_GETDIAG_CONTEXT:
                {
                    char       *contextstackstr;
                    MemoryContext oldcontext;

                    /* Use eval_mcontext for short-lived string */
                    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
                    contextstackstr = GetErrorContextStack();
                    MemoryContextSwitchTo(oldcontext);

                    exec_assign_c_string(estate, var, contextstackstr);
                }
                break;

            default:
                elog(ERROR, "unrecognized diagnostic item kind: %d",
                     diag_item->kind);
        }
    }

    exec_eval_cleanup(estate);

    return PLPGSQL_RC_OK;
}

/* ----------
 * exec_stmt_if                Evaluate a bool expression and
 *                    execute the true or false body
 *                    conditionally.
 * ----------
 */
static int
exec_stmt_if(PLpgSQL_execstate *estate, PLpgSQL_stmt_if *stmt)
{
    bool        value;
    bool        isnull;
    ListCell   *lc;

    value = exec_eval_boolean(estate, stmt->cond, &isnull);
    exec_eval_cleanup(estate);
    if (!isnull && value)
        return exec_stmts(estate, stmt->then_body);

    foreach(lc, stmt->elsif_list)
    {
        PLpgSQL_if_elsif *elif = (PLpgSQL_if_elsif *) lfirst(lc);

        value = exec_eval_boolean(estate, elif->cond, &isnull);
        exec_eval_cleanup(estate);
        if (!isnull && value)
            return exec_stmts(estate, elif->stmts);
    }

    return exec_stmts(estate, stmt->else_body);
}


/*-----------
 * exec_stmt_case
 *-----------
 */
static int
exec_stmt_case(PLpgSQL_execstate *estate, PLpgSQL_stmt_case *stmt)
{// #lizard forgives
    PLpgSQL_var *t_var = NULL;
    bool        isnull;
    ListCell   *l;

    if (stmt->t_expr != NULL)
    {
        /* simple case */
        Datum        t_val;
        Oid            t_typoid;
        int32        t_typmod;

        t_val = exec_eval_expr(estate, stmt->t_expr,
                               &isnull, &t_typoid, &t_typmod);

        t_var = (PLpgSQL_var *) estate->datums[stmt->t_varno];

        /*
         * When expected datatype is different from real, change it. Note that
         * what we're modifying here is an execution copy of the datum, so
         * this doesn't affect the originally stored function parse tree. (In
         * theory, if the expression datatype keeps changing during execution,
         * this could cause a function-lifespan memory leak.  Doesn't seem
         * worth worrying about though.)
         */
        if (t_var->datatype->typoid != t_typoid ||
            t_var->datatype->atttypmod != t_typmod)
            t_var->datatype = plpgsql_build_datatype(t_typoid,
                                                     t_typmod,
                                                     estate->func->fn_input_collation);

        /* now we can assign to the variable */
        exec_assign_value(estate,
                          (PLpgSQL_datum *) t_var,
                          t_val,
                          isnull,
                          t_typoid,
                          t_typmod);

        exec_eval_cleanup(estate);
    }

    /* Now search for a successful WHEN clause */
    foreach(l, stmt->case_when_list)
    {
        PLpgSQL_case_when *cwt = (PLpgSQL_case_when *) lfirst(l);
        bool        value;

        value = exec_eval_boolean(estate, cwt->expr, &isnull);
        exec_eval_cleanup(estate);
        if (!isnull && value)
        {
            /* Found it */

            /* We can now discard any value we had for the temp variable */
            if (t_var != NULL)
                assign_simple_var(estate, t_var, (Datum) 0, true, false);

            /* Evaluate the statement(s), and we're done */
            return exec_stmts(estate, cwt->stmts);
        }
    }

    /* We can now discard any value we had for the temp variable */
    if (t_var != NULL)
        assign_simple_var(estate, t_var, (Datum) 0, true, false);

    /* SQL2003 mandates this error if there was no ELSE clause */
    if (!stmt->have_else)
        ereport(ERROR,
                (errcode(ERRCODE_CASE_NOT_FOUND),
                 errmsg("case not found"),
                 errhint("CASE statement is missing ELSE part.")));

    /* Evaluate the ELSE statements, and we're done */
    return exec_stmts(estate, stmt->else_stmts);
}


/* ----------
 * exec_stmt_loop            Loop over statements until
 *                    an exit occurs.
 * ----------
 */
static int
exec_stmt_loop(PLpgSQL_execstate *estate, PLpgSQL_stmt_loop *stmt)
{// #lizard forgives
    for (;;)
    {
        int            rc = exec_stmts(estate, stmt->body);

        switch (rc)
        {
            case PLPGSQL_RC_OK:
                break;

            case PLPGSQL_RC_EXIT:
                if (estate->exitlabel == NULL)
                    return PLPGSQL_RC_OK;
                if (stmt->label == NULL)
                    return PLPGSQL_RC_EXIT;
                if (strcmp(stmt->label, estate->exitlabel) != 0)
                    return PLPGSQL_RC_EXIT;
                estate->exitlabel = NULL;
                return PLPGSQL_RC_OK;

            case PLPGSQL_RC_CONTINUE:
                if (estate->exitlabel == NULL)
                    /* anonymous continue, so re-run the loop */
                    break;
                else if (stmt->label != NULL &&
                         strcmp(stmt->label, estate->exitlabel) == 0)
                    /* label matches named continue, so re-run loop */
                    estate->exitlabel = NULL;
                else
                    /* label doesn't match named continue, so propagate upward */
                    return PLPGSQL_RC_CONTINUE;
                break;

            case PLPGSQL_RC_RETURN:
                return rc;

            default:
                elog(ERROR, "unrecognized rc: %d", rc);
        }
    }
}


/* ----------
 * exec_stmt_while            Loop over statements as long
 *                    as an expression evaluates to
 *                    true or an exit occurs.
 * ----------
 */
static int
exec_stmt_while(PLpgSQL_execstate *estate, PLpgSQL_stmt_while *stmt)
{// #lizard forgives
    for (;;)
    {
        int            rc;
        bool        value;
        bool        isnull;

        value = exec_eval_boolean(estate, stmt->cond, &isnull);
        exec_eval_cleanup(estate);

        if (isnull || !value)
            break;

        rc = exec_stmts(estate, stmt->body);

        switch (rc)
        {
            case PLPGSQL_RC_OK:
                break;

            case PLPGSQL_RC_EXIT:
                if (estate->exitlabel == NULL)
                    return PLPGSQL_RC_OK;
                if (stmt->label == NULL)
                    return PLPGSQL_RC_EXIT;
                if (strcmp(stmt->label, estate->exitlabel) != 0)
                    return PLPGSQL_RC_EXIT;
                estate->exitlabel = NULL;
                return PLPGSQL_RC_OK;

            case PLPGSQL_RC_CONTINUE:
                if (estate->exitlabel == NULL)
                    /* anonymous continue, so re-run loop */
                    break;
                else if (stmt->label != NULL &&
                         strcmp(stmt->label, estate->exitlabel) == 0)
                    /* label matches named continue, so re-run loop */
                    estate->exitlabel = NULL;
                else
                    /* label doesn't match named continue, propagate upward */
                    return PLPGSQL_RC_CONTINUE;
                break;

            case PLPGSQL_RC_RETURN:
                return rc;

            default:
                elog(ERROR, "unrecognized rc: %d", rc);
        }
    }

    return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmt_fori            Iterate an integer variable
 *                    from a lower to an upper value
 *                    incrementing or decrementing by the BY value
 * ----------
 */
static int
exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
{// #lizard forgives
    PLpgSQL_var *var;
    Datum        value;
    bool        isnull;
    Oid            valtype;
    int32        valtypmod;
    int32        loop_value;
    int32        end_value;
    int32        step_value;
    bool        found = false;
    int            rc = PLPGSQL_RC_OK;

    var = (PLpgSQL_var *) (estate->datums[stmt->var->dno]);

    /*
     * Get the value of the lower bound
     */
    value = exec_eval_expr(estate, stmt->lower,
                           &isnull, &valtype, &valtypmod);
    value = exec_cast_value(estate, value, &isnull,
                            valtype, valtypmod,
                            var->datatype->typoid,
                            var->datatype->atttypmod);
    if (isnull)
        ereport(ERROR,
                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                 errmsg("lower bound of FOR loop cannot be null")));
    loop_value = DatumGetInt32(value);
    exec_eval_cleanup(estate);

    /*
     * Get the value of the upper bound
     */
    value = exec_eval_expr(estate, stmt->upper,
                           &isnull, &valtype, &valtypmod);
    value = exec_cast_value(estate, value, &isnull,
                            valtype, valtypmod,
                            var->datatype->typoid,
                            var->datatype->atttypmod);
    if (isnull)
        ereport(ERROR,
                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                 errmsg("upper bound of FOR loop cannot be null")));
    end_value = DatumGetInt32(value);
    exec_eval_cleanup(estate);

    /*
     * Get the step value
     */
    if (stmt->step)
    {
        value = exec_eval_expr(estate, stmt->step,
                               &isnull, &valtype, &valtypmod);
        value = exec_cast_value(estate, value, &isnull,
                                valtype, valtypmod,
                                var->datatype->typoid,
                                var->datatype->atttypmod);
        if (isnull)
            ereport(ERROR,
                    (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                     errmsg("BY value of FOR loop cannot be null")));
        step_value = DatumGetInt32(value);
        exec_eval_cleanup(estate);
        if (step_value <= 0)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("BY value of FOR loop must be greater than zero")));
    }
    else
        step_value = 1;

    /*
     * Now do the loop
     */
    for (;;)
    {
        /*
         * Check against upper bound
         */
        if (stmt->reverse)
        {
            if (loop_value < end_value)
                break;
        }
        else
        {
            if (loop_value > end_value)
                break;
        }

        found = true;            /* looped at least once */

        /*
         * Assign current value to loop var
         */
        assign_simple_var(estate, var, Int32GetDatum(loop_value), false, false);

        /*
         * Execute the statements
         */
        rc = exec_stmts(estate, stmt->body);

        if (rc == PLPGSQL_RC_RETURN)
            break;                /* break out of the loop */
        else if (rc == PLPGSQL_RC_EXIT)
        {
            if (estate->exitlabel == NULL)
                /* unlabelled exit, finish the current loop */
                rc = PLPGSQL_RC_OK;
            else if (stmt->label != NULL &&
                     strcmp(stmt->label, estate->exitlabel) == 0)
            {
                /* labelled exit, matches the current stmt's label */
                estate->exitlabel = NULL;
                rc = PLPGSQL_RC_OK;
            }

            /*
             * otherwise, this is a labelled exit that does not match the
             * current statement's label, if any: return RC_EXIT so that the
             * EXIT continues to propagate up the stack.
             */
            break;
        }
        else if (rc == PLPGSQL_RC_CONTINUE)
        {
            if (estate->exitlabel == NULL)
                /* unlabelled continue, so re-run the current loop */
                rc = PLPGSQL_RC_OK;
            else if (stmt->label != NULL &&
                     strcmp(stmt->label, estate->exitlabel) == 0)
            {
                /* label matches named continue, so re-run loop */
                estate->exitlabel = NULL;
                rc = PLPGSQL_RC_OK;
            }
            else
            {
                /*
                 * otherwise, this is a named continue that does not match the
                 * current statement's label, if any: return RC_CONTINUE so
                 * that the CONTINUE will propagate up the stack.
                 */
                break;
            }
        }

        /*
         * Increase/decrease loop value, unless it would overflow, in which
         * case exit the loop.
         */
        if (stmt->reverse)
        {
            if ((int32) (loop_value - step_value) > loop_value)
                break;
            loop_value -= step_value;
        }
        else
        {
            if ((int32) (loop_value + step_value) < loop_value)
                break;
            loop_value += step_value;
        }
    }

    /*
     * Set the FOUND variable to indicate the result of executing the loop
     * (namely, whether we looped one or more times). This must be set here so
     * that it does not interfere with the value of the FOUND variable inside
     * the loop processing itself.
     */
    exec_set_found(estate, found);

    return rc;
}


/* ----------
 * exec_stmt_fors            Execute a query, assign each
 *                    tuple to a record or row and
 *                    execute a group of statements
 *                    for it.
 * ----------
 */
static int
exec_stmt_fors(PLpgSQL_execstate *estate, PLpgSQL_stmt_fors *stmt)
{
    Portal        portal;
    int            rc;

    /*
     * Open the implicit cursor for the statement using exec_run_select
     */
    exec_run_select(estate, stmt->query, 0, &portal);

    /*
     * Execute the loop
     */
    rc = exec_for_query(estate, (PLpgSQL_stmt_forq *) stmt, portal, true);

    /*
     * Close the implicit cursor
     */
    SPI_cursor_close(portal);

    return rc;
}


/* ----------
 * exec_stmt_forc            Execute a loop for each row from a cursor.
 * ----------
 */
static int
exec_stmt_forc(PLpgSQL_execstate *estate, PLpgSQL_stmt_forc *stmt)
{// #lizard forgives
    PLpgSQL_var *curvar;
    MemoryContext stmt_mcontext = NULL;
    char       *curname = NULL;
    PLpgSQL_expr *query;
    ParamListInfo paramLI;
    Portal        portal;
    int            rc;

    /* ----------
     * Get the cursor variable and if it has an assigned name, check
     * that it's not in use currently.
     * ----------
     */
    curvar = (PLpgSQL_var *) (estate->datums[stmt->curvar]);
    if (!curvar->isnull)
    {
        MemoryContext oldcontext;

        /* We only need stmt_mcontext to hold the cursor name string */
        stmt_mcontext = get_stmt_mcontext(estate);
        oldcontext = MemoryContextSwitchTo(stmt_mcontext);
        curname = TextDatumGetCString(curvar->value);
        MemoryContextSwitchTo(oldcontext);

        if (SPI_cursor_find(curname) != NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_DUPLICATE_CURSOR),
                     errmsg("cursor \"%s\" already in use", curname)));
    }

    /* ----------
     * Open the cursor just like an OPEN command
     *
     * Note: parser should already have checked that statement supplies
     * args iff cursor needs them, but we check again to be safe.
     * ----------
     */
    if (stmt->argquery != NULL)
    {
        /* ----------
         * OPEN CURSOR with args.  We fake a SELECT ... INTO ...
         * statement to evaluate the args and put 'em into the
         * internal row.
         * ----------
         */
        PLpgSQL_stmt_execsql set_args;

        if (curvar->cursor_explicit_argrow < 0)
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("arguments given for cursor without arguments")));

        memset(&set_args, 0, sizeof(set_args));
        set_args.cmd_type = PLPGSQL_STMT_EXECSQL;
        set_args.lineno = stmt->lineno;
        set_args.sqlstmt = stmt->argquery;
        set_args.into = true;
        /* XXX historically this has not been STRICT */
        set_args.row = (PLpgSQL_row *)
            (estate->datums[curvar->cursor_explicit_argrow]);

        if (exec_stmt_execsql(estate, &set_args) != PLPGSQL_RC_OK)
            elog(ERROR, "open cursor failed during argument processing");
    }
    else
    {
        if (curvar->cursor_explicit_argrow >= 0)
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("arguments required for cursor")));
    }

    query = curvar->cursor_explicit_expr;
    Assert(query);

    if (query->plan == NULL)
        exec_prepare_plan(estate, query, curvar->cursor_options);

    /*
     * Set up short-lived ParamListInfo
     */
    paramLI = setup_unshared_param_list(estate, query);

    /*
     * Open the cursor (the paramlist will get copied into the portal)
     */
    portal = SPI_cursor_open_with_paramlist(curname, query->plan,
                                            paramLI,
                                            estate->readonly_func);
    if (portal == NULL)
        elog(ERROR, "could not open cursor: %s",
             SPI_result_code_string(SPI_result));

    /*
     * If cursor variable was NULL, store the generated portal name in it
     */
    if (curname == NULL)
        assign_text_var(estate, curvar, portal->name);

    /*
     * Clean up before entering exec_for_query
     */
    exec_eval_cleanup(estate);
    if (stmt_mcontext)
        MemoryContextReset(stmt_mcontext);

    /*
     * Execute the loop.  We can't prefetch because the cursor is accessible
     * to the user, for instance via UPDATE WHERE CURRENT OF within the loop.
     */
    rc = exec_for_query(estate, (PLpgSQL_stmt_forq *) stmt, portal, false);

    /* ----------
     * Close portal, and restore cursor variable if it was initially NULL.
     * ----------
     */
    SPI_cursor_close(portal);

    if (curname == NULL)
        assign_simple_var(estate, curvar, (Datum) 0, true, false);

    return rc;
}


/* ----------
 * exec_stmt_foreach_a            Loop over elements or slices of an array
 *
 * When looping over elements, the loop variable is the same type that the
 * array stores (eg: integer), when looping through slices, the loop variable
 * is an array of size and dimensions to match the size of the slice.
 * ----------
 */
static int
exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt)
{// #lizard forgives
    ArrayType  *arr;
    Oid            arrtype;
    int32        arrtypmod;
    PLpgSQL_datum *loop_var;
    Oid            loop_var_elem_type;
    bool        found = false;
    int            rc = PLPGSQL_RC_OK;
    MemoryContext stmt_mcontext;
    MemoryContext oldcontext;
    ArrayIterator array_iterator;
    Oid            iterator_result_type;
    int32        iterator_result_typmod;
    Datum        value;
    bool        isnull;

    /* get the value of the array expression */
    value = exec_eval_expr(estate, stmt->expr, &isnull, &arrtype, &arrtypmod);
    if (isnull)
        ereport(ERROR,
                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                 errmsg("FOREACH expression must not be null")));

    /*
     * Do as much as possible of the code below in stmt_mcontext, to avoid any
     * leaks from called subroutines.  We need a private stmt_mcontext since
     * we'll be calling arbitrary statement code.
     */
    stmt_mcontext = get_stmt_mcontext(estate);
    push_stmt_mcontext(estate);
    oldcontext = MemoryContextSwitchTo(stmt_mcontext);

    /* check the type of the expression - must be an array */
    if (!OidIsValid(get_element_type(arrtype)))
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("FOREACH expression must yield an array, not type %s",
                        format_type_be(arrtype))));

    /*
     * We must copy the array into stmt_mcontext, else it will disappear in
     * exec_eval_cleanup.  This is annoying, but cleanup will certainly happen
     * while running the loop body, so we have little choice.
     */
    arr = DatumGetArrayTypePCopy(value);

    /* Clean up any leftover temporary memory */
    exec_eval_cleanup(estate);

    /* Slice dimension must be less than or equal to array dimension */
    if (stmt->slice < 0 || stmt->slice > ARR_NDIM(arr))
        ereport(ERROR,
                (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
                 errmsg("slice dimension (%d) is out of the valid range 0..%d",
                        stmt->slice, ARR_NDIM(arr))));

    /* Set up the loop variable and see if it is of an array type */
    loop_var = estate->datums[stmt->varno];
    if (loop_var->dtype == PLPGSQL_DTYPE_REC ||
        loop_var->dtype == PLPGSQL_DTYPE_ROW)
    {
        /*
         * Record/row variable is certainly not of array type, and might not
         * be initialized at all yet, so don't try to get its type
         */
        loop_var_elem_type = InvalidOid;
    }
    else
        loop_var_elem_type = get_element_type(plpgsql_exec_get_datum_type(estate,
                                                                          loop_var));

    /*
     * Sanity-check the loop variable type.  We don't try very hard here, and
     * should not be too picky since it's possible that exec_assign_value can
     * coerce values of different types.  But it seems worthwhile to complain
     * if the array-ness of the loop variable is not right.
     */
    if (stmt->slice > 0 && loop_var_elem_type == InvalidOid)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("FOREACH ... SLICE loop variable must be of an array type")));
    if (stmt->slice == 0 && loop_var_elem_type != InvalidOid)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("FOREACH loop variable must not be of an array type")));

    /* Create an iterator to step through the array */
    array_iterator = array_create_iterator(arr, stmt->slice, NULL);

    /* Identify iterator result type */
    if (stmt->slice > 0)
    {
        /* When slicing, nominal type of result is same as array type */
        iterator_result_type = arrtype;
        iterator_result_typmod = arrtypmod;
    }
    else
    {
        /* Without slicing, results are individual array elements */
        iterator_result_type = ARR_ELEMTYPE(arr);
        iterator_result_typmod = arrtypmod;
    }

    /* Iterate over the array elements or slices */
    while (array_iterate(array_iterator, &value, &isnull))
    {
        found = true;            /* looped at least once */

        /* exec_assign_value and exec_stmts must run in the main context */
        MemoryContextSwitchTo(oldcontext);

        /* Assign current element/slice to the loop variable */
        exec_assign_value(estate, loop_var, value, isnull,
                          iterator_result_type, iterator_result_typmod);

        /* In slice case, value is temporary; must free it to avoid leakage */
        if (stmt->slice > 0)
            pfree(DatumGetPointer(value));

        /*
         * Execute the statements
         */
        rc = exec_stmts(estate, stmt->body);

        /* Handle the return code */
        if (rc == PLPGSQL_RC_RETURN)
            break;                /* break out of the loop */
        else if (rc == PLPGSQL_RC_EXIT)
        {
            if (estate->exitlabel == NULL)
                /* unlabelled exit, finish the current loop */
                rc = PLPGSQL_RC_OK;
            else if (stmt->label != NULL &&
                     strcmp(stmt->label, estate->exitlabel) == 0)
            {
                /* labelled exit, matches the current stmt's label */
                estate->exitlabel = NULL;
                rc = PLPGSQL_RC_OK;
            }

            /*
             * otherwise, this is a labelled exit that does not match the
             * current statement's label, if any: return RC_EXIT so that the
             * EXIT continues to propagate up the stack.
             */
            break;
        }
        else if (rc == PLPGSQL_RC_CONTINUE)
        {
            if (estate->exitlabel == NULL)
                /* unlabelled continue, so re-run the current loop */
                rc = PLPGSQL_RC_OK;
            else if (stmt->label != NULL &&
                     strcmp(stmt->label, estate->exitlabel) == 0)
            {
                /* label matches named continue, so re-run loop */
                estate->exitlabel = NULL;
                rc = PLPGSQL_RC_OK;
            }
            else
            {
                /*
                 * otherwise, this is a named continue that does not match the
                 * current statement's label, if any: return RC_CONTINUE so
                 * that the CONTINUE will propagate up the stack.
                 */
                break;
            }
        }

        MemoryContextSwitchTo(stmt_mcontext);
    }

    /* Restore memory context state */
    MemoryContextSwitchTo(oldcontext);
    pop_stmt_mcontext(estate);

    /* Release temporary memory, including the array value */
    MemoryContextReset(stmt_mcontext);

    /*
     * Set the FOUND variable to indicate the result of executing the loop
     * (namely, whether we looped one or more times). This must be set here so
     * that it does not interfere with the value of the FOUND variable inside
     * the loop processing itself.
     */
    exec_set_found(estate, found);

    return rc;
}


/* ----------
 * exec_stmt_exit            Implements EXIT and CONTINUE
 *
 * This begins the process of exiting / restarting a loop.
 * ----------
 */
static int
exec_stmt_exit(PLpgSQL_execstate *estate, PLpgSQL_stmt_exit *stmt)
{
    /*
     * If the exit / continue has a condition, evaluate it
     */
    if (stmt->cond != NULL)
    {
        bool        value;
        bool        isnull;

        value = exec_eval_boolean(estate, stmt->cond, &isnull);
        exec_eval_cleanup(estate);
        if (isnull || value == false)
            return PLPGSQL_RC_OK;
    }

    estate->exitlabel = stmt->label;
    if (stmt->is_exit)
        return PLPGSQL_RC_EXIT;
    else
        return PLPGSQL_RC_CONTINUE;
}


/* ----------
 * exec_stmt_return            Evaluate an expression and start
 *                    returning from the function.
 *
 * Note: in the retistuple code paths, the returned tuple is always in the
 * function's main context, whereas for non-tuple data types the result may
 * be in the eval_mcontext.  The former case is not a memory leak since we're
 * about to exit the function anyway.  (If you want to change it, note that
 * exec_stmt_block() knows about this behavior.)  The latter case means that
 * we must not do exec_eval_cleanup while unwinding the control stack.
 * ----------
 */
static int
exec_stmt_return(PLpgSQL_execstate *estate, PLpgSQL_stmt_return *stmt)
{// #lizard forgives
    /*
     * If processing a set-returning PL/pgSQL function, the final RETURN
     * indicates that the function is finished producing tuples.  The rest of
     * the work will be done at the top level.
     */
    if (estate->retisset)
        return PLPGSQL_RC_RETURN;

    /* initialize for null result (possibly a tuple) */
    estate->retval = (Datum) 0;
    estate->rettupdesc = NULL;
    estate->retisnull = true;
    estate->rettype = InvalidOid;

    /*
     * Special case path when the RETURN expression is a simple variable
     * reference; in particular, this path is always taken in functions with
     * one or more OUT parameters.
     *
     * This special case is especially efficient for returning variables that
     * have R/W expanded values: we can put the R/W pointer directly into
     * estate->retval, leading to transferring the value to the caller's
     * context cheaply.  If we went through exec_eval_expr we'd end up with a
     * R/O pointer.  It's okay to skip MakeExpandedObjectReadOnly here since
     * we know we won't need the variable's value within the function anymore.
     */
    if (stmt->retvarno >= 0)
    {
        PLpgSQL_datum *retvar = estate->datums[stmt->retvarno];

        switch (retvar->dtype)
        {
            case PLPGSQL_DTYPE_VAR:
                {
                    PLpgSQL_var *var = (PLpgSQL_var *) retvar;

                    estate->retval = var->value;
                    estate->retisnull = var->isnull;
                    estate->rettype = var->datatype->typoid;

                    /*
                     * Cope with retistuple case.  A PLpgSQL_var could not be
                     * of composite type, so we needn't make any effort to
                     * convert.  However, for consistency with the expression
                     * code path, don't throw error if the result is NULL.
                     */
                    if (estate->retistuple && !estate->retisnull)
                        ereport(ERROR,
                                (errcode(ERRCODE_DATATYPE_MISMATCH),
                                 errmsg("cannot return non-composite value from function returning composite type")));
                }
                break;

            case PLPGSQL_DTYPE_REC:
                {
                    PLpgSQL_rec *rec = (PLpgSQL_rec *) retvar;
                    int32        rettypmod;

                    if (HeapTupleIsValid(rec->tup))
                    {
                        if (estate->retistuple)
                        {
                            estate->retval = PointerGetDatum(rec->tup);
                            estate->rettupdesc = rec->tupdesc;
                            estate->retisnull = false;
                        }
                        else
                            exec_eval_datum(estate,
                                            retvar,
                                            &estate->rettype,
                                            &rettypmod,
                                            &estate->retval,
                                            &estate->retisnull);
                    }
                }
                break;

            case PLPGSQL_DTYPE_ROW:
                {
                    PLpgSQL_row *row = (PLpgSQL_row *) retvar;
                    int32        rettypmod;

                    if (estate->retistuple)
                    {
                        HeapTuple    tup;

                        if (!row->rowtupdesc)    /* should not happen */
                            elog(ERROR, "row variable has no tupdesc");
                        tup = make_tuple_from_row(estate, row, row->rowtupdesc);
                        if (tup == NULL)    /* should not happen */
                            elog(ERROR, "row not compatible with its own tupdesc");
                        estate->retval = PointerGetDatum(tup);
                        estate->rettupdesc = row->rowtupdesc;
                        estate->retisnull = false;
                    }
                    else
                        exec_eval_datum(estate,
                                        retvar,
                                        &estate->rettype,
                                        &rettypmod,
                                        &estate->retval,
                                        &estate->retisnull);
                }
                break;

            default:
                elog(ERROR, "unrecognized dtype: %d", retvar->dtype);
        }

        return PLPGSQL_RC_RETURN;
    }

    if (stmt->expr != NULL)
    {
        int32        rettypmod;

        estate->retval = exec_eval_expr(estate, stmt->expr,
                                        &(estate->retisnull),
                                        &(estate->rettype),
                                        &rettypmod);

        if (estate->retistuple && !estate->retisnull)
        {
            /* Convert composite datum to a HeapTuple and TupleDesc */
            HeapTuple    tuple;
            TupleDesc    tupdesc;

            /* Source must be of RECORD or composite type */
            if (!type_is_rowtype(estate->rettype))
                ereport(ERROR,
                        (errcode(ERRCODE_DATATYPE_MISMATCH),
                         errmsg("cannot return non-composite value from function returning composite type")));
            tuple = get_tuple_from_datum(estate->retval);
            tupdesc = get_tupdesc_from_datum(estate->retval);
            estate->retval = PointerGetDatum(tuple);
            estate->rettupdesc = CreateTupleDescCopy(tupdesc);
            ReleaseTupleDesc(tupdesc);
        }

        return PLPGSQL_RC_RETURN;
    }

    /*
     * Special hack for function returning VOID: instead of NULL, return a
     * non-null VOID value.  This is of dubious importance but is kept for
     * backwards compatibility.
     */
    if (estate->fn_rettype == VOIDOID)
    {
        estate->retval = (Datum) 0;
        estate->retisnull = false;
        estate->rettype = VOIDOID;
    }

    return PLPGSQL_RC_RETURN;
}

/* ----------
 * exec_stmt_return_next        Evaluate an expression and add it to the
 *                                list of tuples returned by the current
 *                                SRF.
 * ----------
 */
static int
exec_stmt_return_next(PLpgSQL_execstate *estate,
                      PLpgSQL_stmt_return_next *stmt)
{// #lizard forgives
    TupleDesc    tupdesc;
    int            natts;
    HeapTuple    tuple;
    MemoryContext oldcontext;

    if (!estate->retisset)
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg("cannot use RETURN NEXT in a non-SETOF function")));

    if (estate->tuple_store == NULL)
        exec_init_tuple_store(estate);

    /* rettupdesc will be filled by exec_init_tuple_store */
    tupdesc = estate->rettupdesc;
    natts = tupdesc->natts;

    /*
     * Special case path when the RETURN NEXT expression is a simple variable
     * reference; in particular, this path is always taken in functions with
     * one or more OUT parameters.
     *
     * Unlike exec_statement_return, there's no special win here for R/W
     * expanded values, since they'll have to get flattened to go into the
     * tuplestore.  Indeed, we'd better make them R/O to avoid any risk of the
     * casting step changing them in-place.
     */
    if (stmt->retvarno >= 0)
    {
        PLpgSQL_datum *retvar = estate->datums[stmt->retvarno];

        switch (retvar->dtype)
        {
            case PLPGSQL_DTYPE_VAR:
                {
                    PLpgSQL_var *var = (PLpgSQL_var *) retvar;
                    Datum        retval = var->value;
                    bool        isNull = var->isnull;

                    if (natts != 1)
                        ereport(ERROR,
                                (errcode(ERRCODE_DATATYPE_MISMATCH),
                                 errmsg("wrong result type supplied in RETURN NEXT")));

                    /* let's be very paranoid about the cast step */
                    retval = MakeExpandedObjectReadOnly(retval,
                                                        isNull,
                                                        var->datatype->typlen);

                    /* coerce type if needed */
                    retval = exec_cast_value(estate,
                                             retval,
                                             &isNull,
                                             var->datatype->typoid,
                                             var->datatype->atttypmod,
                                             tupdesc->attrs[0]->atttypid,
                                             tupdesc->attrs[0]->atttypmod);

                    tuplestore_putvalues(estate->tuple_store, tupdesc,
                                         &retval, &isNull);
                }
                break;

            case PLPGSQL_DTYPE_REC:
                {
                    PLpgSQL_rec *rec = (PLpgSQL_rec *) retvar;
                    TupleConversionMap *tupmap;

                    if (!HeapTupleIsValid(rec->tup))
                        ereport(ERROR,
                                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                                 errmsg("record \"%s\" is not assigned yet",
                                        rec->refname),
                                 errdetail("The tuple structure of a not-yet-assigned"
                                           " record is indeterminate.")));

                    /* Use eval_mcontext for tuple conversion work */
                    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
                    tupmap = convert_tuples_by_position(rec->tupdesc,
                                                        tupdesc,
                                                        gettext_noop("wrong record type supplied in RETURN NEXT"));
                    tuple = rec->tup;
                    if (tupmap)
                        tuple = do_convert_tuple(tuple, tupmap, NULL);
                    tuplestore_puttuple(estate->tuple_store, tuple);
                    MemoryContextSwitchTo(oldcontext);
                }
                break;

            case PLPGSQL_DTYPE_ROW:
                {
                    PLpgSQL_row *row = (PLpgSQL_row *) retvar;

                    /* Use eval_mcontext for tuple conversion work */
                    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
                    tuple = make_tuple_from_row(estate, row, tupdesc);
                    if (tuple == NULL)
                        ereport(ERROR,
                                (errcode(ERRCODE_DATATYPE_MISMATCH),
                                 errmsg("wrong record type supplied in RETURN NEXT")));
                    tuplestore_puttuple(estate->tuple_store, tuple);
                    MemoryContextSwitchTo(oldcontext);
                }
                break;

            default:
                elog(ERROR, "unrecognized dtype: %d", retvar->dtype);
                break;
        }
    }
    else if (stmt->expr)
    {
        Datum        retval;
        bool        isNull;
        Oid            rettype;
        int32        rettypmod;

        retval = exec_eval_expr(estate,
                                stmt->expr,
                                &isNull,
                                &rettype,
                                &rettypmod);

        if (estate->retistuple)
        {
            /* Expression should be of RECORD or composite type */
            if (!isNull)
            {
                TupleDesc    retvaldesc;
                TupleConversionMap *tupmap;

                if (!type_is_rowtype(rettype))
                    ereport(ERROR,
                            (errcode(ERRCODE_DATATYPE_MISMATCH),
                             errmsg("cannot return non-composite value from function returning composite type")));

                /* Use eval_mcontext for tuple conversion work */
                oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
                tuple = get_tuple_from_datum(retval);
                retvaldesc = get_tupdesc_from_datum(retval);
                tupmap = convert_tuples_by_position(retvaldesc, tupdesc,
                                                    gettext_noop("returned record type does not match expected record type"));
                if (tupmap)
                    tuple = do_convert_tuple(tuple, tupmap, NULL);
                tuplestore_puttuple(estate->tuple_store, tuple);
                ReleaseTupleDesc(retvaldesc);
                MemoryContextSwitchTo(oldcontext);
            }
            else
            {
                /* Composite NULL --- store a row of nulls */
                Datum       *nulldatums;
                bool       *nullflags;

                nulldatums = (Datum *)
                    eval_mcontext_alloc0(estate, natts * sizeof(Datum));
                nullflags = (bool *)
                    eval_mcontext_alloc(estate, natts * sizeof(bool));
                memset(nullflags, true, natts * sizeof(bool));
                tuplestore_putvalues(estate->tuple_store, tupdesc,
                                     nulldatums, nullflags);
            }
        }
        else
        {
            /* Simple scalar result */
            if (natts != 1)
                ereport(ERROR,
                        (errcode(ERRCODE_DATATYPE_MISMATCH),
                         errmsg("wrong result type supplied in RETURN NEXT")));

            /* coerce type if needed */
            retval = exec_cast_value(estate,
                                     retval,
                                     &isNull,
                                     rettype,
                                     rettypmod,
                                     tupdesc->attrs[0]->atttypid,
                                     tupdesc->attrs[0]->atttypmod);

            tuplestore_putvalues(estate->tuple_store, tupdesc,
                                 &retval, &isNull);
        }
    }
    else
    {
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg("RETURN NEXT must have a parameter")));
    }

    exec_eval_cleanup(estate);

    return PLPGSQL_RC_OK;
}

/* ----------
 * exec_stmt_return_query        Evaluate a query and add it to the
 *                                list of tuples returned by the current
 *                                SRF.
 * ----------
 */
static int
exec_stmt_return_query(PLpgSQL_execstate *estate,
                       PLpgSQL_stmt_return_query *stmt)
{// #lizard forgives
    Portal        portal;
    uint64        processed = 0;
    TupleConversionMap *tupmap;
    MemoryContext oldcontext;

    if (!estate->retisset)
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg("cannot use RETURN QUERY in a non-SETOF function")));

    if (estate->tuple_store == NULL)
        exec_init_tuple_store(estate);

    if (stmt->query != NULL)
    {
        /* static query */
        exec_run_select(estate, stmt->query, 0, &portal);
    }
    else
    {
        /* RETURN QUERY EXECUTE */
        Assert(stmt->dynquery != NULL);
        portal = exec_dynquery_with_params(estate, stmt->dynquery,
                                           stmt->params, NULL,
                                           0);
    }

    /* Use eval_mcontext for tuple conversion work */
    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));

    tupmap = convert_tuples_by_position(portal->tupDesc,
                                        estate->rettupdesc,
                                        gettext_noop("structure of query does not match function result type"));

    while (true)
    {
        uint64        i;

        SPI_cursor_fetch(portal, true, 50);

        /* SPI will have changed CurrentMemoryContext */
        MemoryContextSwitchTo(get_eval_mcontext(estate));

        if (SPI_processed == 0)
            break;

        for (i = 0; i < SPI_processed; i++)
        {
            HeapTuple    tuple = SPI_tuptable->vals[i];

            if (tupmap)
                tuple = do_convert_tuple(tuple, tupmap, NULL);
            tuplestore_puttuple(estate->tuple_store, tuple);
            if (tupmap)
                heap_freetuple(tuple);
            processed++;
        }

        SPI_freetuptable(SPI_tuptable);
    }

    SPI_freetuptable(SPI_tuptable);
    SPI_cursor_close(portal);

    MemoryContextSwitchTo(oldcontext);
    exec_eval_cleanup(estate);

    estate->eval_processed = processed;
    exec_set_found(estate, processed != 0);

    return PLPGSQL_RC_OK;
}

static void
exec_init_tuple_store(PLpgSQL_execstate *estate)
{
    ReturnSetInfo *rsi = estate->rsi;
    MemoryContext oldcxt;
    ResourceOwner oldowner;

    /*
     * Check caller can handle a set result in the way we want
     */
    if (!rsi || !IsA(rsi, ReturnSetInfo) ||
        (rsi->allowedModes & SFRM_Materialize) == 0 ||
        rsi->expectedDesc == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("set-valued function called in context that cannot accept a set")));

    /*
     * Switch to the right memory context and resource owner for storing the
     * tuplestore for return set. If we're within a subtransaction opened for
     * an exception-block, for example, we must still create the tuplestore in
     * the resource owner that was active when this function was entered, and
     * not in the subtransaction resource owner.
     */
    oldcxt = MemoryContextSwitchTo(estate->tuple_store_cxt);
    oldowner = CurrentResourceOwner;
    CurrentResourceOwner = estate->tuple_store_owner;

    estate->tuple_store =
        tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
                              false, work_mem);

    CurrentResourceOwner = oldowner;
    MemoryContextSwitchTo(oldcxt);

    estate->rettupdesc = rsi->expectedDesc;
}

#define SET_RAISE_OPTION_TEXT(opt, name) \
do { \
    if (opt) \
        ereport(ERROR, \
                (errcode(ERRCODE_SYNTAX_ERROR), \
                 errmsg("RAISE option already specified: %s", \
                        name))); \
    opt = MemoryContextStrdup(stmt_mcontext, extval); \
} while (0)

/* ----------
 * exec_stmt_raise            Build a message and throw it with elog()
 * ----------
 */
static int
exec_stmt_raise(PLpgSQL_execstate *estate, PLpgSQL_stmt_raise *stmt)
{// #lizard forgives
    int            err_code = 0;
    char       *condname = NULL;
    char       *err_message = NULL;
    char       *err_detail = NULL;
    char       *err_hint = NULL;
    char       *err_column = NULL;
    char       *err_constraint = NULL;
    char       *err_datatype = NULL;
    char       *err_table = NULL;
    char       *err_schema = NULL;
    MemoryContext stmt_mcontext;
    ListCell   *lc;

    /* RAISE with no parameters: re-throw current exception */
    if (stmt->condname == NULL && stmt->message == NULL &&
        stmt->options == NIL)
    {
        if (estate->cur_error != NULL)
            ReThrowError(estate->cur_error);
        /* oops, we're not inside a handler */
        ereport(ERROR,
                (errcode(ERRCODE_STACKED_DIAGNOSTICS_ACCESSED_WITHOUT_ACTIVE_HANDLER),
                 errmsg("RAISE without parameters cannot be used outside an exception handler")));
    }

    /* We'll need to accumulate the various strings in stmt_mcontext */
    stmt_mcontext = get_stmt_mcontext(estate);

    if (stmt->condname)
    {
        err_code = plpgsql_recognize_err_condition(stmt->condname, true);
        condname = MemoryContextStrdup(stmt_mcontext, stmt->condname);
    }

    if (stmt->message)
    {
        StringInfoData ds;
        ListCell   *current_param;
        char       *cp;
        MemoryContext oldcontext;

        /* build string in stmt_mcontext */
        oldcontext = MemoryContextSwitchTo(stmt_mcontext);
        initStringInfo(&ds);
        MemoryContextSwitchTo(oldcontext);

        current_param = list_head(stmt->params);

        for (cp = stmt->message; *cp; cp++)
        {
            /*
             * Occurrences of a single % are replaced by the next parameter's
             * external representation. Double %'s are converted to one %.
             */
            if (cp[0] == '%')
            {
                Oid            paramtypeid;
                int32        paramtypmod;
                Datum        paramvalue;
                bool        paramisnull;
                char       *extval;

                if (cp[1] == '%')
                {
                    appendStringInfoChar(&ds, '%');
                    cp++;
                    continue;
                }

                /* should have been checked at compile time */
                if (current_param == NULL)
                    elog(ERROR, "unexpected RAISE parameter list length");

                paramvalue = exec_eval_expr(estate,
                                            (PLpgSQL_expr *) lfirst(current_param),
                                            &paramisnull,
                                            &paramtypeid,
                                            &paramtypmod);

                if (paramisnull)
                    extval = "<NULL>";
                else
                    extval = convert_value_to_string(estate,
                                                     paramvalue,
                                                     paramtypeid);
                appendStringInfoString(&ds, extval);
                current_param = lnext(current_param);
                exec_eval_cleanup(estate);
            }
            else
                appendStringInfoChar(&ds, cp[0]);
        }

        /* should have been checked at compile time */
        if (current_param != NULL)
            elog(ERROR, "unexpected RAISE parameter list length");

        err_message = ds.data;
    }

    foreach(lc, stmt->options)
    {
        PLpgSQL_raise_option *opt = (PLpgSQL_raise_option *) lfirst(lc);
        Datum        optionvalue;
        bool        optionisnull;
        Oid            optiontypeid;
        int32        optiontypmod;
        char       *extval;

        optionvalue = exec_eval_expr(estate, opt->expr,
                                     &optionisnull,
                                     &optiontypeid,
                                     &optiontypmod);
        if (optionisnull)
            ereport(ERROR,
                    (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                     errmsg("RAISE statement option cannot be null")));

        extval = convert_value_to_string(estate, optionvalue, optiontypeid);

        switch (opt->opt_type)
        {
            case PLPGSQL_RAISEOPTION_ERRCODE:
                if (err_code)
                    ereport(ERROR,
                            (errcode(ERRCODE_SYNTAX_ERROR),
                             errmsg("RAISE option already specified: %s",
                                    "ERRCODE")));
                err_code = plpgsql_recognize_err_condition(extval, true);
                condname = MemoryContextStrdup(stmt_mcontext, extval);
                break;
            case PLPGSQL_RAISEOPTION_MESSAGE:
                SET_RAISE_OPTION_TEXT(err_message, "MESSAGE");
                break;
            case PLPGSQL_RAISEOPTION_DETAIL:
                SET_RAISE_OPTION_TEXT(err_detail, "DETAIL");
                break;
            case PLPGSQL_RAISEOPTION_HINT:
                SET_RAISE_OPTION_TEXT(err_hint, "HINT");
                break;
            case PLPGSQL_RAISEOPTION_COLUMN:
                SET_RAISE_OPTION_TEXT(err_column, "COLUMN");
                break;
            case PLPGSQL_RAISEOPTION_CONSTRAINT:
                SET_RAISE_OPTION_TEXT(err_constraint, "CONSTRAINT");
                break;
            case PLPGSQL_RAISEOPTION_DATATYPE:
                SET_RAISE_OPTION_TEXT(err_datatype, "DATATYPE");
                break;
            case PLPGSQL_RAISEOPTION_TABLE:
                SET_RAISE_OPTION_TEXT(err_table, "TABLE");
                break;
            case PLPGSQL_RAISEOPTION_SCHEMA:
                SET_RAISE_OPTION_TEXT(err_schema, "SCHEMA");
                break;
            default:
                elog(ERROR, "unrecognized raise option: %d", opt->opt_type);
        }

        exec_eval_cleanup(estate);
    }

    /* Default code if nothing specified */
    if (err_code == 0 && stmt->elog_level >= ERROR)
        err_code = ERRCODE_RAISE_EXCEPTION;

    /* Default error message if nothing specified */
    if (err_message == NULL)
    {
        if (condname)
        {
            err_message = condname;
            condname = NULL;
        }
        else
            err_message = MemoryContextStrdup(stmt_mcontext,
                                              unpack_sql_state(err_code));
    }

    /*
     * Throw the error (may or may not come back)
     */
    ereport(stmt->elog_level,
            (err_code ? errcode(err_code) : 0,
             errmsg_internal("%s", err_message),
             (err_detail != NULL) ? errdetail_internal("%s", err_detail) : 0,
             (err_hint != NULL) ? errhint("%s", err_hint) : 0,
             (err_column != NULL) ?
             err_generic_string(PG_DIAG_COLUMN_NAME, err_column) : 0,
             (err_constraint != NULL) ?
             err_generic_string(PG_DIAG_CONSTRAINT_NAME, err_constraint) : 0,
             (err_datatype != NULL) ?
             err_generic_string(PG_DIAG_DATATYPE_NAME, err_datatype) : 0,
             (err_table != NULL) ?
             err_generic_string(PG_DIAG_TABLE_NAME, err_table) : 0,
             (err_schema != NULL) ?
             err_generic_string(PG_DIAG_SCHEMA_NAME, err_schema) : 0));

    /* Clean up transient strings */
    MemoryContextReset(stmt_mcontext);

    return PLPGSQL_RC_OK;
}

/* ----------
 * exec_stmt_assert            Assert statement
 * ----------
 */
static int
exec_stmt_assert(PLpgSQL_execstate *estate, PLpgSQL_stmt_assert *stmt)
{
    bool        value;
    bool        isnull;

    /* do nothing when asserts are not enabled */
    if (!plpgsql_check_asserts)
        return PLPGSQL_RC_OK;

    value = exec_eval_boolean(estate, stmt->cond, &isnull);
    exec_eval_cleanup(estate);

    if (isnull || !value)
    {
        char       *message = NULL;

        if (stmt->message != NULL)
        {
            Datum        val;
            Oid            typeid;
            int32        typmod;

            val = exec_eval_expr(estate, stmt->message,
                                 &isnull, &typeid, &typmod);
            if (!isnull)
                message = convert_value_to_string(estate, val, typeid);
            /* we mustn't do exec_eval_cleanup here */
        }

        ereport(ERROR,
                (errcode(ERRCODE_ASSERT_FAILURE),
                 message ? errmsg_internal("%s", message) :
                 errmsg("assertion failed")));
    }

    return PLPGSQL_RC_OK;
}

/* ----------
 * Initialize a mostly empty execution state
 * ----------
 */
static void
plpgsql_estate_setup(PLpgSQL_execstate *estate,
                     PLpgSQL_function *func,
                     ReturnSetInfo *rsi,
                     EState *simple_eval_estate)
{
    HASHCTL        ctl;

    /* this link will be restored at exit from plpgsql_call_handler */
    func->cur_estate = estate;

    estate->func = func;

    estate->retval = (Datum) 0;
    estate->retisnull = true;
    estate->rettype = InvalidOid;

    estate->fn_rettype = func->fn_rettype;
    estate->retistuple = func->fn_retistuple;
    estate->retisset = func->fn_retset;

    estate->readonly_func = func->fn_readonly;

    estate->rettupdesc = NULL;
    estate->exitlabel = NULL;
    estate->cur_error = NULL;

    estate->tuple_store = NULL;
    estate->handle_exceptions = false;

    if (rsi)
    {
        estate->tuple_store_cxt = rsi->econtext->ecxt_per_query_memory;
        estate->tuple_store_owner = CurrentResourceOwner;
    }
    else
    {
        estate->tuple_store_cxt = NULL;
        estate->tuple_store_owner = NULL;
    }
    estate->rsi = rsi;

    estate->found_varno = func->found_varno;
    estate->ndatums = func->ndatums;
    estate->datums = palloc(sizeof(PLpgSQL_datum *) * estate->ndatums);
    /* caller is expected to fill the datums array */

    /* initialize ParamListInfo with one entry per datum, all invalid */
    estate->paramLI = (ParamListInfo)
        palloc0(offsetof(ParamListInfoData, params) +
                estate->ndatums * sizeof(ParamExternData));
    estate->paramLI->paramFetch = plpgsql_param_fetch;
    estate->paramLI->paramFetchArg = (void *) estate;
    estate->paramLI->parserSetup = (ParserSetupHook) plpgsql_parser_setup;
    estate->paramLI->parserSetupArg = NULL; /* filled during use */
    estate->paramLI->numParams = estate->ndatums;
    estate->paramLI->paramMask = NULL;
    estate->params_dirty = false;

    /* set up for use of appropriate simple-expression EState and cast hash */
    if (simple_eval_estate)
    {
        estate->simple_eval_estate = simple_eval_estate;
        /* Private cast hash just lives in function's main context */
        memset(&ctl, 0, sizeof(ctl));
        ctl.keysize = sizeof(plpgsql_CastHashKey);
        ctl.entrysize = sizeof(plpgsql_CastHashEntry);
        ctl.hcxt = CurrentMemoryContext;
        estate->cast_hash = hash_create("PLpgSQL private cast cache",
                                        16, /* start small and extend */
                                        &ctl,
                                        HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
        estate->cast_hash_context = CurrentMemoryContext;
    }
    else
    {
        estate->simple_eval_estate = shared_simple_eval_estate;
        /* Create the session-wide cast-info hash table if we didn't already */
        if (shared_cast_hash == NULL)
        {
            shared_cast_context = AllocSetContextCreate(TopMemoryContext,
                                                        "PLpgSQL cast info",
                                                        ALLOCSET_DEFAULT_SIZES);
            memset(&ctl, 0, sizeof(ctl));
            ctl.keysize = sizeof(plpgsql_CastHashKey);
            ctl.entrysize = sizeof(plpgsql_CastHashEntry);
            ctl.hcxt = shared_cast_context;
            shared_cast_hash = hash_create("PLpgSQL cast cache",
                                           16,    /* start small and extend */
                                           &ctl,
                                           HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
        }
        estate->cast_hash = shared_cast_hash;
        estate->cast_hash_context = shared_cast_context;
    }

    /*
     * We start with no stmt_mcontext; one will be created only if needed.
     * That context will be a direct child of the function's main execution
     * context.  Additional stmt_mcontexts might be created as children of it.
     */
    estate->stmt_mcontext = NULL;
    estate->stmt_mcontext_parent = CurrentMemoryContext;

    estate->eval_tuptable = NULL;
    estate->eval_processed = 0;
    estate->eval_lastoid = InvalidOid;
    estate->eval_econtext = NULL;

    estate->err_stmt = NULL;
    estate->err_text = NULL;

    estate->plugin_info = NULL;

    /*
     * Create an EState and ExprContext for evaluation of simple expressions.
     */
    plpgsql_create_econtext(estate);

    /*
     * Let the plugin see this function before we initialize any local
     * PL/pgSQL variables - note that we also give the plugin a few function
     * pointers so it can call back into PL/pgSQL for doing things like
     * variable assignments and stack traces
     */
    if (*plpgsql_plugin_ptr)
    {
        (*plpgsql_plugin_ptr)->error_callback = plpgsql_exec_error_callback;
        (*plpgsql_plugin_ptr)->assign_expr = exec_assign_expr;

        if ((*plpgsql_plugin_ptr)->func_setup)
            ((*plpgsql_plugin_ptr)->func_setup) (estate, func);
    }
}

/* ----------
 * Release temporary memory used by expression/subselect evaluation
 *
 * NB: the result of the evaluation is no longer valid after this is done,
 * unless it is a pass-by-value datatype.
 *
 * NB: if you change this code, see also the hacks in exec_assign_value's
 * PLPGSQL_DTYPE_ARRAYELEM case for partial cleanup after subscript evals.
 * ----------
 */
static void
exec_eval_cleanup(PLpgSQL_execstate *estate)
{
    /* Clear result of a full SPI_execute */
    if (estate->eval_tuptable != NULL)
        SPI_freetuptable(estate->eval_tuptable);
    estate->eval_tuptable = NULL;

    /*
     * Clear result of exec_eval_simple_expr (but keep the econtext).  This
     * also clears any short-lived allocations done via get_eval_mcontext.
     */
    if (estate->eval_econtext != NULL)
        ResetExprContext(estate->eval_econtext);
}


/* ----------
 * Generate a prepared plan
 * ----------
 */
static void
exec_prepare_plan(PLpgSQL_execstate *estate,
                  PLpgSQL_expr *expr, int cursorOptions)
{
    SPIPlanPtr    plan;

    /*
     * The grammar can't conveniently set expr->func while building the parse
     * tree, so make sure it's set before parser hooks need it.
     */
    expr->func = estate->func;

    /*
     * Generate and save the plan
     */
    plan = SPI_prepare_params(expr->query,
                              (ParserSetupHook) plpgsql_parser_setup,
                              (void *) expr,
                              cursorOptions);
    if (plan == NULL)
    {
        /* Some SPI errors deserve specific error messages */
        switch (SPI_result)
        {
            case SPI_ERROR_COPY:
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("cannot COPY to/from client in PL/pgSQL")));
            case SPI_ERROR_TRANSACTION:
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("cannot begin/end transactions in PL/pgSQL"),
                         errhint("Use a BEGIN block with an EXCEPTION clause instead.")));
            default:
                elog(ERROR, "SPI_prepare_params failed for \"%s\": %s",
                     expr->query, SPI_result_code_string(SPI_result));
        }
    }
    SPI_keepplan(plan);
    expr->plan = plan;

    /* Check to see if it's a simple expression */
    exec_simple_check_plan(estate, expr);

    /*
     * Mark expression as not using a read-write param.  exec_assign_value has
     * to take steps to override this if appropriate; that seems cleaner than
     * adding parameters to all other callers.
     */
    expr->rwparam = -1;
}


/* ----------
 * exec_stmt_execsql            Execute an SQL statement (possibly with INTO).
 *
 * Note: some callers rely on this not touching stmt_mcontext.  If it ever
 * needs to use that, fix those callers to push/pop stmt_mcontext.
 * ----------
 */
static int
exec_stmt_execsql(PLpgSQL_execstate *estate,
                  PLpgSQL_stmt_execsql *stmt)
{// #lizard forgives
    ParamListInfo paramLI;
    long        tcount;
    int            rc;
    PLpgSQL_expr *expr = stmt->sqlstmt;

    /*
     * On the first call for this statement generate the plan, and detect
     * whether the statement is INSERT/UPDATE/DELETE
     */
    if (expr->plan == NULL)
    {
        ListCell   *l;

        exec_prepare_plan(estate, expr, CURSOR_OPT_PARALLEL_OK);
        stmt->mod_stmt = false;
        foreach(l, SPI_plan_get_plan_sources(expr->plan))
        {
            CachedPlanSource *plansource = (CachedPlanSource *) lfirst(l);
            ListCell   *l2;

            foreach(l2, plansource->query_list)
            {
                Query       *q = lfirst_node(Query, l2);

                if (q->canSetTag)
                {
                    if (q->commandType == CMD_INSERT ||
                        q->commandType == CMD_UPDATE ||
                        q->commandType == CMD_DELETE)
                        stmt->mod_stmt = true;

					/* when transform insert to copy, reset mod_stmt */
					if (g_transform_insert_to_copy && q->commandType == CMD_INSERT &&
						q->isMultiValues && !q->hasUnshippableTriggers)
						stmt->mod_stmt = false;
                    /* PGXCTODO: Support a better parameter interface for XC with DMLs */
                    if
#ifdef XCP
                       (IS_PGXC_DATANODE && !enable_datanode_row_triggers &&
#endif
                        (q->commandType == CMD_INSERT ||
                         q->commandType == CMD_UPDATE ||
                         q->commandType == CMD_DELETE)
#ifdef XCP
                       )
#endif
                         ereport(ERROR,
                                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                 errmsg("Postgres-XL does not support DML queries in PL/pgSQL on Datanodes")));
                }
            }
        }
    }

    /*
     * Set up ParamListInfo to pass to executor
     */
    paramLI = setup_param_list(estate, expr);

    /*
     * If we have INTO, then we only need one row back ... but if we have INTO
     * STRICT, ask for two rows, so that we can verify the statement returns
     * only one.  INSERT/UPDATE/DELETE are always treated strictly. Without
     * INTO, just run the statement to completion (tcount = 0).
     *
     * We could just ask for two rows always when using INTO, but there are
     * some cases where demanding the extra row costs significant time, eg by
     * forcing completion of a sequential scan.  So don't do it unless we need
     * to enforce strictness.
     */
    if (stmt->into)
    {
        if (stmt->strict || stmt->mod_stmt)
            tcount = 2;
        else
            tcount = 1;
    }
    else
        tcount = 0;

    /*
     * Execute the plan
     */
    rc = SPI_execute_plan_with_paramlist(expr->plan, paramLI,
                                         estate->readonly_func, tcount);

    /*
     * Check for error, and set FOUND if appropriate (for historical reasons
     * we set FOUND only for certain query types).  Also Assert that we
     * identified the statement type the same as SPI did.
     */
    switch (rc)
    {
        case SPI_OK_SELECT:
            Assert(!stmt->mod_stmt);
            exec_set_found(estate, (SPI_processed != 0));
            break;

        case SPI_OK_INSERT:
        case SPI_OK_UPDATE:
        case SPI_OK_DELETE:
        case SPI_OK_INSERT_RETURNING:
        case SPI_OK_UPDATE_RETURNING:
        case SPI_OK_DELETE_RETURNING:
            Assert(stmt->mod_stmt);
            exec_set_found(estate, (SPI_processed != 0));
            break;

        case SPI_OK_SELINTO:
        case SPI_OK_UTILITY:
            Assert(!stmt->mod_stmt);
            break;

        case SPI_OK_REWRITTEN:
            Assert(!stmt->mod_stmt);

            /*
             * The command was rewritten into another kind of command. It's
             * not clear what FOUND would mean in that case (and SPI doesn't
             * return the row count either), so just set it to false.
             */
            exec_set_found(estate, false);
            break;

            /* Some SPI errors deserve specific error messages */
        case SPI_ERROR_COPY:
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("cannot COPY to/from client in PL/pgSQL")));
        case SPI_ERROR_TRANSACTION:
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("cannot begin/end transactions in PL/pgSQL"),
                     errhint("Use a BEGIN block with an EXCEPTION clause instead.")));

        default:
            elog(ERROR, "SPI_execute_plan_with_paramlist failed executing query \"%s\": %s",
                 expr->query, SPI_result_code_string(rc));
    }

    /* All variants should save result info for GET DIAGNOSTICS */
    estate->eval_processed = SPI_processed;
    estate->eval_lastoid = SPI_lastoid;

    /* Process INTO if present */
    if (stmt->into)
    {
        SPITupleTable *tuptab = SPI_tuptable;
        uint64        n = SPI_processed;
        PLpgSQL_rec *rec = NULL;
        PLpgSQL_row *row = NULL;

        /* If the statement did not return a tuple table, complain */
        if (tuptab == NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("INTO used with a command that cannot return data")));

        /* Determine if we assign to a record or a row */
        if (stmt->rec != NULL)
            rec = (PLpgSQL_rec *) (estate->datums[stmt->rec->dno]);
        else if (stmt->row != NULL)
            row = (PLpgSQL_row *) (estate->datums[stmt->row->dno]);
        else
            elog(ERROR, "unsupported target");

        /*
         * If SELECT ... INTO specified STRICT, and the query didn't find
         * exactly one row, throw an error.  If STRICT was not specified, then
         * allow the query to find any number of rows.
         */
        if (n == 0)
        {
            if (stmt->strict)
            {
                char       *errdetail;

                if (estate->func->print_strict_params)
                    errdetail = format_expr_params(estate, expr);
                else
                    errdetail = NULL;

                ereport(ERROR,
                        (errcode(ERRCODE_NO_DATA_FOUND),
                         errmsg("query returned no rows"),
                         errdetail ? errdetail_internal("parameters: %s", errdetail) : 0));
            }
            /* set the target to NULL(s) */
            exec_move_row(estate, rec, row, NULL, tuptab->tupdesc);
        }
        else
        {
            if (n > 1 && (stmt->strict || stmt->mod_stmt))
            {
                char       *errdetail;

                if (estate->func->print_strict_params)
                    errdetail = format_expr_params(estate, expr);
                else
                    errdetail = NULL;

                ereport(ERROR,
                        (errcode(ERRCODE_TOO_MANY_ROWS),
                         errmsg("query returned more than one row"),
                         errdetail ? errdetail_internal("parameters: %s", errdetail) : 0));
            }
            /* Put the first result row into the target */
            exec_move_row(estate, rec, row, tuptab->vals[0], tuptab->tupdesc);
        }

        /* Clean up */
        exec_eval_cleanup(estate);
        SPI_freetuptable(SPI_tuptable);
    }
    else
    {
        /* If the statement returned a tuple table, complain */
        if (SPI_tuptable != NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("query has no destination for result data"),
                     (rc == SPI_OK_SELECT) ? errhint("If you want to discard the results of a SELECT, use PERFORM instead.") : 0));
    }

    return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmt_dynexecute            Execute a dynamic SQL query
 *                    (possibly with INTO).
 * ----------
 */
static int
exec_stmt_dynexecute(PLpgSQL_execstate *estate,
                     PLpgSQL_stmt_dynexecute *stmt)
{// #lizard forgives
    Datum        query;
    bool        isnull;
    Oid            restype;
    int32        restypmod;
    char       *querystr;
    int            exec_res;
    PreparedParamsData *ppd = NULL;
    MemoryContext stmt_mcontext = get_stmt_mcontext(estate);

    /*
     * First we evaluate the string expression after the EXECUTE keyword. Its
     * result is the querystring we have to execute.
     */
    query = exec_eval_expr(estate, stmt->query, &isnull, &restype, &restypmod);
    if (isnull)
        ereport(ERROR,
                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                 errmsg("query string argument of EXECUTE is null")));

    /* Get the C-String representation */
    querystr = convert_value_to_string(estate, query, restype);

    /* copy it into the stmt_mcontext before we clean up */
    querystr = MemoryContextStrdup(stmt_mcontext, querystr);

    exec_eval_cleanup(estate);

    /*
     * Execute the query without preparing a saved plan.
     */
    if (stmt->params)
    {
        ppd = exec_eval_using_params(estate, stmt->params);
        exec_res = SPI_execute_with_args(querystr,
                                         ppd->nargs, ppd->types,
                                         ppd->values, ppd->nulls,
                                         estate->readonly_func, 0);
    }
    else
        exec_res = SPI_execute(querystr, estate->readonly_func, 0);

    switch (exec_res)
    {
        case SPI_OK_SELECT:
        case SPI_OK_INSERT:
        case SPI_OK_UPDATE:
        case SPI_OK_DELETE:
        case SPI_OK_INSERT_RETURNING:
        case SPI_OK_UPDATE_RETURNING:
        case SPI_OK_DELETE_RETURNING:
        case SPI_OK_UTILITY:
        case SPI_OK_REWRITTEN:
            break;

        case 0:

            /*
             * Also allow a zero return, which implies the querystring
             * contained no commands.
             */
            break;

        case SPI_OK_SELINTO:

            /*
             * We want to disallow SELECT INTO for now, because its behavior
             * is not consistent with SELECT INTO in a normal plpgsql context.
             * (We need to reimplement EXECUTE to parse the string as a
             * plpgsql command, not just feed it to SPI_execute.)  This is not
             * a functional limitation because CREATE TABLE AS is allowed.
             */
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("EXECUTE of SELECT ... INTO is not implemented"),
                     errhint("You might want to use EXECUTE ... INTO or EXECUTE CREATE TABLE ... AS instead.")));
            break;

            /* Some SPI errors deserve specific error messages */
        case SPI_ERROR_COPY:
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("cannot COPY to/from client in PL/pgSQL")));
        case SPI_ERROR_TRANSACTION:
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("cannot begin/end transactions in PL/pgSQL"),
                     errhint("Use a BEGIN block with an EXCEPTION clause instead.")));

        default:
            elog(ERROR, "SPI_execute failed executing query \"%s\": %s",
                 querystr, SPI_result_code_string(exec_res));
            break;
    }

    /* Save result info for GET DIAGNOSTICS */
    estate->eval_processed = SPI_processed;
    estate->eval_lastoid = SPI_lastoid;

    /* Process INTO if present */
    if (stmt->into)
    {
        SPITupleTable *tuptab = SPI_tuptable;
        uint64        n = SPI_processed;
        PLpgSQL_rec *rec = NULL;
        PLpgSQL_row *row = NULL;

        /* If the statement did not return a tuple table, complain */
        if (tuptab == NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("INTO used with a command that cannot return data")));

        /* Determine if we assign to a record or a row */
        if (stmt->rec != NULL)
            rec = (PLpgSQL_rec *) (estate->datums[stmt->rec->dno]);
        else if (stmt->row != NULL)
            row = (PLpgSQL_row *) (estate->datums[stmt->row->dno]);
        else
            elog(ERROR, "unsupported target");

        /*
         * If SELECT ... INTO specified STRICT, and the query didn't find
         * exactly one row, throw an error.  If STRICT was not specified, then
         * allow the query to find any number of rows.
         */
        if (n == 0)
        {
            if (stmt->strict)
            {
                char       *errdetail;

                if (estate->func->print_strict_params)
                    errdetail = format_preparedparamsdata(estate, ppd);
                else
                    errdetail = NULL;

                ereport(ERROR,
                        (errcode(ERRCODE_NO_DATA_FOUND),
                         errmsg("query returned no rows"),
                         errdetail ? errdetail_internal("parameters: %s", errdetail) : 0));
            }
            /* set the target to NULL(s) */
            exec_move_row(estate, rec, row, NULL, tuptab->tupdesc);
        }
        else
        {
            if (n > 1 && stmt->strict)
            {
                char       *errdetail;

                if (estate->func->print_strict_params)
                    errdetail = format_preparedparamsdata(estate, ppd);
                else
                    errdetail = NULL;

                ereport(ERROR,
                        (errcode(ERRCODE_TOO_MANY_ROWS),
                         errmsg("query returned more than one row"),
                         errdetail ? errdetail_internal("parameters: %s", errdetail) : 0));
            }

            /* Put the first result row into the target */
            exec_move_row(estate, rec, row, tuptab->vals[0], tuptab->tupdesc);
        }
        /* clean up after exec_move_row() */
        exec_eval_cleanup(estate);
    }
    else
    {
        /*
         * It might be a good idea to raise an error if the query returned
         * tuples that are being ignored, but historically we have not done
         * that.
         */
    }

    /* Release any result from SPI_execute, as well as transient data */
    SPI_freetuptable(SPI_tuptable);
    MemoryContextReset(stmt_mcontext);

    return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmt_dynfors            Execute a dynamic query, assign each
 *                    tuple to a record or row and
 *                    execute a group of statements
 *                    for it.
 * ----------
 */
static int
exec_stmt_dynfors(PLpgSQL_execstate *estate, PLpgSQL_stmt_dynfors *stmt)
{
    Portal        portal;
    int            rc;

    portal = exec_dynquery_with_params(estate, stmt->query, stmt->params,
                                       NULL, 0);

    /*
     * Execute the loop
     */
    rc = exec_for_query(estate, (PLpgSQL_stmt_forq *) stmt, portal, true);

    /*
     * Close the implicit cursor
     */
    SPI_cursor_close(portal);

    return rc;
}


/* ----------
 * exec_stmt_open            Execute an OPEN cursor statement
 * ----------
 */
static int
exec_stmt_open(PLpgSQL_execstate *estate, PLpgSQL_stmt_open *stmt)
{// #lizard forgives
    PLpgSQL_var *curvar;
    MemoryContext stmt_mcontext = NULL;
    char       *curname = NULL;
    PLpgSQL_expr *query;
    Portal        portal;
    ParamListInfo paramLI;

    /* ----------
     * Get the cursor variable and if it has an assigned name, check
     * that it's not in use currently.
     * ----------
     */
    curvar = (PLpgSQL_var *) (estate->datums[stmt->curvar]);
    if (!curvar->isnull)
    {
        MemoryContext oldcontext;

        /* We only need stmt_mcontext to hold the cursor name string */
        stmt_mcontext = get_stmt_mcontext(estate);
        oldcontext = MemoryContextSwitchTo(stmt_mcontext);
        curname = TextDatumGetCString(curvar->value);
        MemoryContextSwitchTo(oldcontext);

        if (SPI_cursor_find(curname) != NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_DUPLICATE_CURSOR),
                     errmsg("cursor \"%s\" already in use", curname)));
    }

    /* ----------
     * Process the OPEN according to it's type.
     * ----------
     */
    if (stmt->query != NULL)
    {
        /* ----------
         * This is an OPEN refcursor FOR SELECT ...
         *
         * We just make sure the query is planned. The real work is
         * done downstairs.
         * ----------
         */
        query = stmt->query;
        if (query->plan == NULL)
            exec_prepare_plan(estate, query, stmt->cursor_options);
    }
    else if (stmt->dynquery != NULL)
    {
        /* ----------
         * This is an OPEN refcursor FOR EXECUTE ...
         * ----------
         */
        portal = exec_dynquery_with_params(estate,
                                           stmt->dynquery,
                                           stmt->params,
                                           curname,
                                           stmt->cursor_options);

        /*
         * If cursor variable was NULL, store the generated portal name in it.
         * Note: exec_dynquery_with_params already reset the stmt_mcontext, so
         * curname is a dangling pointer here; but testing it for nullness is
         * OK.
         */
        if (curname == NULL)
            assign_text_var(estate, curvar, portal->name);

        return PLPGSQL_RC_OK;
    }
    else
    {
        /* ----------
         * This is an OPEN cursor
         *
         * Note: parser should already have checked that statement supplies
         * args iff cursor needs them, but we check again to be safe.
         * ----------
         */
        if (stmt->argquery != NULL)
        {
            /* ----------
             * OPEN CURSOR with args.  We fake a SELECT ... INTO ...
             * statement to evaluate the args and put 'em into the
             * internal row.
             * ----------
             */
            PLpgSQL_stmt_execsql set_args;

            if (curvar->cursor_explicit_argrow < 0)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("arguments given for cursor without arguments")));

            memset(&set_args, 0, sizeof(set_args));
            set_args.cmd_type = PLPGSQL_STMT_EXECSQL;
            set_args.lineno = stmt->lineno;
            set_args.sqlstmt = stmt->argquery;
            set_args.into = true;
            /* XXX historically this has not been STRICT */
            set_args.row = (PLpgSQL_row *)
                (estate->datums[curvar->cursor_explicit_argrow]);

            if (exec_stmt_execsql(estate, &set_args) != PLPGSQL_RC_OK)
                elog(ERROR, "open cursor failed during argument processing");
        }
        else
        {
            if (curvar->cursor_explicit_argrow >= 0)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("arguments required for cursor")));
        }

        query = curvar->cursor_explicit_expr;
        if (query->plan == NULL)
            exec_prepare_plan(estate, query, curvar->cursor_options);
    }

    /*
     * Set up short-lived ParamListInfo
     */
    paramLI = setup_unshared_param_list(estate, query);

    /*
     * Open the cursor
     */
    portal = SPI_cursor_open_with_paramlist(curname, query->plan,
                                            paramLI,
                                            estate->readonly_func);
    if (portal == NULL)
        elog(ERROR, "could not open cursor: %s",
             SPI_result_code_string(SPI_result));

    /*
     * If cursor variable was NULL, store the generated portal name in it
     */
    if (curname == NULL)
        assign_text_var(estate, curvar, portal->name);

    /* If we had any transient data, clean it up */
    exec_eval_cleanup(estate);
    if (stmt_mcontext)
        MemoryContextReset(stmt_mcontext);

    return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmt_fetch            Fetch from a cursor into a target, or just
 *                            move the current position of the cursor
 * ----------
 */
static int
exec_stmt_fetch(PLpgSQL_execstate *estate, PLpgSQL_stmt_fetch *stmt)
{// #lizard forgives
    PLpgSQL_var *curvar;
    PLpgSQL_rec *rec = NULL;
    PLpgSQL_row *row = NULL;
    long        how_many = stmt->how_many;
    SPITupleTable *tuptab;
    Portal        portal;
    char       *curname;
    uint64        n;
    MemoryContext oldcontext;

    /* ----------
     * Get the portal of the cursor by name
     * ----------
     */
    curvar = (PLpgSQL_var *) (estate->datums[stmt->curvar]);
    if (curvar->isnull)
        ereport(ERROR,
                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                 errmsg("cursor variable \"%s\" is null", curvar->refname)));

    /* Use eval_mcontext for short-lived string */
    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
    curname = TextDatumGetCString(curvar->value);
    MemoryContextSwitchTo(oldcontext);

    portal = SPI_cursor_find(curname);
    if (portal == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_CURSOR),
                 errmsg("cursor \"%s\" does not exist", curname)));

    /* Calculate position for FETCH_RELATIVE or FETCH_ABSOLUTE */
    if (stmt->expr)
    {
        bool        isnull;

        /* XXX should be doing this in LONG not INT width */
        how_many = exec_eval_integer(estate, stmt->expr, &isnull);

        if (isnull)
            ereport(ERROR,
                    (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                     errmsg("relative or absolute cursor position is null")));

        exec_eval_cleanup(estate);
    }

    if (!stmt->is_move)
    {
        /* ----------
         * Determine if we fetch into a record or a row
         * ----------
         */
        if (stmt->rec != NULL)
            rec = (PLpgSQL_rec *) (estate->datums[stmt->rec->dno]);
        else if (stmt->row != NULL)
            row = (PLpgSQL_row *) (estate->datums[stmt->row->dno]);
        else
            elog(ERROR, "unsupported target");

        /* ----------
         * Fetch 1 tuple from the cursor
         * ----------
         */
        SPI_scroll_cursor_fetch(portal, stmt->direction, how_many);
        tuptab = SPI_tuptable;
        n = SPI_processed;

        /* ----------
         * Set the target appropriately.
         * ----------
         */
        if (n == 0)
            exec_move_row(estate, rec, row, NULL, tuptab->tupdesc);
        else
            exec_move_row(estate, rec, row, tuptab->vals[0], tuptab->tupdesc);

        exec_eval_cleanup(estate);
        SPI_freetuptable(tuptab);
    }
    else
    {
        /* Move the cursor */
        SPI_scroll_cursor_move(portal, stmt->direction, how_many);
        n = SPI_processed;
    }

    /* Set the ROW_COUNT and the global FOUND variable appropriately. */
    estate->eval_processed = n;
    exec_set_found(estate, n != 0);

    return PLPGSQL_RC_OK;
}

/* ----------
 * exec_stmt_close            Close a cursor
 * ----------
 */
static int
exec_stmt_close(PLpgSQL_execstate *estate, PLpgSQL_stmt_close *stmt)
{
    PLpgSQL_var *curvar;
    Portal        portal;
    char       *curname;
    MemoryContext oldcontext;

    /* ----------
     * Get the portal of the cursor by name
     * ----------
     */
    curvar = (PLpgSQL_var *) (estate->datums[stmt->curvar]);
    if (curvar->isnull)
        ereport(ERROR,
                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                 errmsg("cursor variable \"%s\" is null", curvar->refname)));

    /* Use eval_mcontext for short-lived string */
    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
    curname = TextDatumGetCString(curvar->value);
    MemoryContextSwitchTo(oldcontext);

    portal = SPI_cursor_find(curname);
    if (portal == NULL)
    {
        if (estate->handle_exceptions)
            return PLPGSQL_RC_OK;

        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_CURSOR),
                 errmsg("cursor \"%s\" does not exist", curname)));
    }

    /* ----------
     * And close it.
     * ----------
     */
    SPI_cursor_close(portal);

    return PLPGSQL_RC_OK;
}


/* ----------
 * exec_assign_expr            Put an expression's result into a variable.
 * ----------
 */
static void
exec_assign_expr(PLpgSQL_execstate *estate, PLpgSQL_datum *target,
                 PLpgSQL_expr *expr)
{
    Datum        value;
    bool        isnull;
    Oid            valtype;
    int32        valtypmod;

    /*
     * If first time through, create a plan for this expression, and then see
     * if we can pass the target variable as a read-write parameter to the
     * expression.  (This is a bit messy, but it seems cleaner than modifying
     * the API of exec_eval_expr for the purpose.)
     */
    if (expr->plan == NULL)
    {
        exec_prepare_plan(estate, expr, 0);
        if (target->dtype == PLPGSQL_DTYPE_VAR)
            exec_check_rw_parameter(expr, target->dno);
    }

    value = exec_eval_expr(estate, expr, &isnull, &valtype, &valtypmod);
    exec_assign_value(estate, target, value, isnull, valtype, valtypmod);
    exec_eval_cleanup(estate);
}


/* ----------
 * exec_assign_c_string        Put a C string into a text variable.
 *
 * We take a NULL pointer as signifying empty string, not SQL null.
 *
 * As with the underlying exec_assign_value, caller is expected to do
 * exec_eval_cleanup later.
 * ----------
 */
static void
exec_assign_c_string(PLpgSQL_execstate *estate, PLpgSQL_datum *target,
                     const char *str)
{
    text       *value;
    MemoryContext oldcontext;

    /* Use eval_mcontext for short-lived text value */
    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
    if (str != NULL)
        value = cstring_to_text(str);
    else
        value = cstring_to_text("");
    MemoryContextSwitchTo(oldcontext);

    exec_assign_value(estate, target, PointerGetDatum(value), false,
                      TEXTOID, -1);
}


/* ----------
 * exec_assign_value            Put a value into a target datum
 *
 * Note: in some code paths, this will leak memory in the eval_mcontext;
 * we assume that will be cleaned up later by exec_eval_cleanup.  We cannot
 * call exec_eval_cleanup here for fear of destroying the input Datum value.
 * ----------
 */
static void
exec_assign_value(PLpgSQL_execstate *estate,
                  PLpgSQL_datum *target,
                  Datum value, bool isNull,
                  Oid valtype, int32 valtypmod)
{// #lizard forgives
    switch (target->dtype)
    {
        case PLPGSQL_DTYPE_VAR:
            {
                /*
                 * Target is a variable
                 */
                PLpgSQL_var *var = (PLpgSQL_var *) target;
                Datum        newvalue;

                newvalue = exec_cast_value(estate,
                                           value,
                                           &isNull,
                                           valtype,
                                           valtypmod,
                                           var->datatype->typoid,
                                           var->datatype->atttypmod);

                if (isNull && var->notnull)
                    ereport(ERROR,
                            (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                             errmsg("null value cannot be assigned to variable \"%s\" declared NOT NULL",
                                    var->refname)));

                /*
                 * If type is by-reference, copy the new value (which is
                 * probably in the eval_mcontext) into the procedure's main
                 * memory context.  But if it's a read/write reference to an
                 * expanded object, no physical copy needs to happen; at most
                 * we need to reparent the object's memory context.
                 *
                 * If it's an array, we force the value to be stored in R/W
                 * expanded form.  This wins if the function later does, say,
                 * a lot of array subscripting operations on the variable, and
                 * otherwise might lose.  We might need to use a different
                 * heuristic, but it's too soon to tell.  Also, are there
                 * cases where it'd be useful to force non-array values into
                 * expanded form?
                 */
                if (!var->datatype->typbyval && !isNull)
                {
                    if (var->datatype->typisarray &&
                        !VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(newvalue)))
                    {
                        /* array and not already R/W, so apply expand_array */
                        newvalue = expand_array(newvalue,
                                                CurrentMemoryContext,
                                                NULL);
                    }
                    else
                    {
                        /* else transfer value if R/W, else just datumCopy */
                        newvalue = datumTransfer(newvalue,
                                                 false,
                                                 var->datatype->typlen);
                    }
                }

                /*
                 * Now free the old value, if any, and assign the new one. But
                 * skip the assignment if old and new values are the same.
                 * Note that for expanded objects, this test is necessary and
                 * cannot reliably be made any earlier; we have to be looking
                 * at the object's standard R/W pointer to be sure pointer
                 * equality is meaningful.
                 */
                if (var->value != newvalue || var->isnull || isNull)
                    assign_simple_var(estate, var, newvalue, isNull,
                                      (!var->datatype->typbyval && !isNull));
                break;
            }

        case PLPGSQL_DTYPE_ROW:
            {
                /*
                 * Target is a row variable
                 */
                PLpgSQL_row *row = (PLpgSQL_row *) target;

                if (isNull)
                {
                    /* If source is null, just assign nulls to the row */
                    exec_move_row(estate, NULL, row, NULL, NULL);
                }
                else
                {
                    /* Source must be of RECORD or composite type */
                    if (!type_is_rowtype(valtype))
                        ereport(ERROR,
                                (errcode(ERRCODE_DATATYPE_MISMATCH),
                                 errmsg("cannot assign non-composite value to a row variable")));
                    exec_move_row_from_datum(estate, NULL, row, value);
                }
                break;
            }

        case PLPGSQL_DTYPE_REC:
            {
                /*
                 * Target is a record variable
                 */
                PLpgSQL_rec *rec = (PLpgSQL_rec *) target;

                if (isNull)
                {
                    /* If source is null, just assign nulls to the record */
                    exec_move_row(estate, rec, NULL, NULL, NULL);
                }
                else
                {
                    /* Source must be of RECORD or composite type */
                    if (!type_is_rowtype(valtype))
                        ereport(ERROR,
                                (errcode(ERRCODE_DATATYPE_MISMATCH),
                                 errmsg("cannot assign non-composite value to a record variable")));
                    exec_move_row_from_datum(estate, rec, NULL, value);
                }
                break;
            }

        case PLPGSQL_DTYPE_RECFIELD:
            {
                /*
                 * Target is a field of a record
                 */
                PLpgSQL_recfield *recfield = (PLpgSQL_recfield *) target;
                PLpgSQL_rec *rec;
                int            fno;
                HeapTuple    newtup;
                int            colnums[1];
                Datum        values[1];
                bool        nulls[1];
                Oid            atttype;
                int32        atttypmod;

                rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);

                /*
                 * Check that there is already a tuple in the record. We need
                 * that because records don't have any predefined field
                 * structure.
                 */
                if (!HeapTupleIsValid(rec->tup))
                    ereport(ERROR,
                            (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                             errmsg("record \"%s\" is not assigned yet",
                                    rec->refname),
                             errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));

                /*
                 * Get the number of the record field to change.  Disallow
                 * system columns because the code below won't cope.
                 */
                fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
                if (fno <= 0)
                    ereport(ERROR,
                            (errcode(ERRCODE_UNDEFINED_COLUMN),
                             errmsg("record \"%s\" has no field \"%s\"",
                                    rec->refname, recfield->fieldname)));
                colnums[0] = fno;

                /*
                 * Now insert the new value, being careful to cast it to the
                 * right type.
                 */
                atttype = rec->tupdesc->attrs[fno - 1]->atttypid;
                atttypmod = rec->tupdesc->attrs[fno - 1]->atttypmod;
                values[0] = exec_cast_value(estate,
                                            value,
                                            &isNull,
                                            valtype,
                                            valtypmod,
                                            atttype,
                                            atttypmod);
                nulls[0] = isNull;

                newtup = heap_modify_tuple_by_cols(rec->tup, rec->tupdesc,
                                                   1, colnums, values, nulls);

                if (rec->freetup)
                    heap_freetuple(rec->tup);

                rec->tup = newtup;
                rec->freetup = true;

                break;
            }

        case PLPGSQL_DTYPE_ARRAYELEM:
            {
                /*
                 * Target is an element of an array
                 */
                PLpgSQL_arrayelem *arrayelem;
                int            nsubscripts;
                int            i;
                PLpgSQL_expr *subscripts[MAXDIM];
                int            subscriptvals[MAXDIM];
                Datum        oldarraydatum,
                            newarraydatum,
                            coerced_value;
                bool        oldarrayisnull;
                Oid            parenttypoid;
                int32        parenttypmod;
                SPITupleTable *save_eval_tuptable;
                MemoryContext oldcontext;

                /*
                 * We need to do subscript evaluation, which might require
                 * evaluating general expressions; and the caller might have
                 * done that too in order to prepare the input Datum.  We have
                 * to save and restore the caller's SPI_execute result, if
                 * any.
                 */
                save_eval_tuptable = estate->eval_tuptable;
                estate->eval_tuptable = NULL;

                /*
                 * To handle constructs like x[1][2] := something, we have to
                 * be prepared to deal with a chain of arrayelem datums. Chase
                 * back to find the base array datum, and save the subscript
                 * expressions as we go.  (We are scanning right to left here,
                 * but want to evaluate the subscripts left-to-right to
                 * minimize surprises.)  Note that arrayelem is left pointing
                 * to the leftmost arrayelem datum, where we will cache the
                 * array element type data.
                 */
                nsubscripts = 0;
                do
                {
                    arrayelem = (PLpgSQL_arrayelem *) target;
                    if (nsubscripts >= MAXDIM)
                        ereport(ERROR,
                                (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
                                 errmsg("number of array dimensions (%d) exceeds the maximum allowed (%d)",
                                        nsubscripts + 1, MAXDIM)));
                    subscripts[nsubscripts++] = arrayelem->subscript;
                    target = estate->datums[arrayelem->arrayparentno];
                } while (target->dtype == PLPGSQL_DTYPE_ARRAYELEM);

                /* Fetch current value of array datum */
                exec_eval_datum(estate, target,
                                &parenttypoid, &parenttypmod,
                                &oldarraydatum, &oldarrayisnull);

                /* Update cached type data if necessary */
                if (arrayelem->parenttypoid != parenttypoid ||
                    arrayelem->parenttypmod != parenttypmod)
                {
                    Oid            arraytypoid;
                    int32        arraytypmod = parenttypmod;
                    int16        arraytyplen;
                    Oid            elemtypoid;
                    int16        elemtyplen;
                    bool        elemtypbyval;
                    char        elemtypalign;

                    /* If target is domain over array, reduce to base type */
                    arraytypoid = getBaseTypeAndTypmod(parenttypoid,
                                                       &arraytypmod);

                    /* ... and identify the element type */
                    elemtypoid = get_element_type(arraytypoid);
                    if (!OidIsValid(elemtypoid))
                        ereport(ERROR,
                                (errcode(ERRCODE_DATATYPE_MISMATCH),
                                 errmsg("subscripted object is not an array")));

                    /* Collect needed data about the types */
                    arraytyplen = get_typlen(arraytypoid);

                    get_typlenbyvalalign(elemtypoid,
                                         &elemtyplen,
                                         &elemtypbyval,
                                         &elemtypalign);

                    /* Now safe to update the cached data */
                    arrayelem->parenttypoid = parenttypoid;
                    arrayelem->parenttypmod = parenttypmod;
                    arrayelem->arraytypoid = arraytypoid;
                    arrayelem->arraytypmod = arraytypmod;
                    arrayelem->arraytyplen = arraytyplen;
                    arrayelem->elemtypoid = elemtypoid;
                    arrayelem->elemtyplen = elemtyplen;
                    arrayelem->elemtypbyval = elemtypbyval;
                    arrayelem->elemtypalign = elemtypalign;
                }

                /*
                 * Evaluate the subscripts, switch into left-to-right order.
                 * Like the expression built by ExecInitArrayRef(), complain
                 * if any subscript is null.
                 */
                for (i = 0; i < nsubscripts; i++)
                {
                    bool        subisnull;

                    subscriptvals[i] =
                        exec_eval_integer(estate,
                                          subscripts[nsubscripts - 1 - i],
                                          &subisnull);
                    if (subisnull)
                        ereport(ERROR,
                                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                                 errmsg("array subscript in assignment must not be null")));

                    /*
                     * Clean up in case the subscript expression wasn't
                     * simple. We can't do exec_eval_cleanup, but we can do
                     * this much (which is safe because the integer subscript
                     * value is surely pass-by-value), and we must do it in
                     * case the next subscript expression isn't simple either.
                     */
                    if (estate->eval_tuptable != NULL)
                        SPI_freetuptable(estate->eval_tuptable);
                    estate->eval_tuptable = NULL;
                }

                /* Now we can restore caller's SPI_execute result if any. */
                Assert(estate->eval_tuptable == NULL);
                estate->eval_tuptable = save_eval_tuptable;

                /* Coerce source value to match array element type. */
                coerced_value = exec_cast_value(estate,
                                                value,
                                                &isNull,
                                                valtype,
                                                valtypmod,
                                                arrayelem->elemtypoid,
                                                arrayelem->arraytypmod);

                /*
                 * If the original array is null, cons up an empty array so
                 * that the assignment can proceed; we'll end with a
                 * one-element array containing just the assigned-to
                 * subscript.  This only works for varlena arrays, though; for
                 * fixed-length array types we skip the assignment.  We can't
                 * support assignment of a null entry into a fixed-length
                 * array, either, so that's a no-op too.  This is all ugly but
                 * corresponds to the current behavior of execExpr*.c.
                 */
                if (arrayelem->arraytyplen > 0 &&    /* fixed-length array? */
                    (oldarrayisnull || isNull))
                    return;

                /* empty array, if any, and newarraydatum are short-lived */
                oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));

                if (oldarrayisnull)
                    oldarraydatum = PointerGetDatum(construct_empty_array(arrayelem->elemtypoid));

                /*
                 * Build the modified array value.
                 */
                newarraydatum = array_set_element(oldarraydatum,
                                                  nsubscripts,
                                                  subscriptvals,
                                                  coerced_value,
                                                  isNull,
                                                  arrayelem->arraytyplen,
                                                  arrayelem->elemtyplen,
                                                  arrayelem->elemtypbyval,
                                                  arrayelem->elemtypalign);

                MemoryContextSwitchTo(oldcontext);

                /*
                 * Assign the new array to the base variable.  It's never NULL
                 * at this point.  Note that if the target is a domain,
                 * coercing the base array type back up to the domain will
                 * happen within exec_assign_value.
                 */
                exec_assign_value(estate, target,
                                  newarraydatum,
                                  false,
                                  arrayelem->arraytypoid,
                                  arrayelem->arraytypmod);
                break;
            }

        default:
            elog(ERROR, "unrecognized dtype: %d", target->dtype);
    }
}

/*
 * exec_eval_datum                Get current value of a PLpgSQL_datum
 *
 * The type oid, typmod, value in Datum format, and null flag are returned.
 *
 * At present this doesn't handle PLpgSQL_expr or PLpgSQL_arrayelem datums;
 * that's not needed because we never pass references to such datums to SPI.
 *
 * NOTE: the returned Datum points right at the stored value in the case of
 * pass-by-reference datatypes.  Generally callers should take care not to
 * modify the stored value.  Some callers intentionally manipulate variables
 * referenced by R/W expanded pointers, though; it is those callers'
 * responsibility that the results are semantically OK.
 *
 * In some cases we have to palloc a return value, and in such cases we put
 * it into the estate's eval_mcontext.
 */
static void
exec_eval_datum(PLpgSQL_execstate *estate,
                PLpgSQL_datum *datum,
                Oid *typeid,
                int32 *typetypmod,
                Datum *value,
                bool *isnull)
{// #lizard forgives
    MemoryContext oldcontext;

    switch (datum->dtype)
    {
        case PLPGSQL_DTYPE_VAR:
            {
                PLpgSQL_var *var = (PLpgSQL_var *) datum;

                *typeid = var->datatype->typoid;
                *typetypmod = var->datatype->atttypmod;
                *value = var->value;
                *isnull = var->isnull;
                break;
            }

        case PLPGSQL_DTYPE_ROW:
            {
                PLpgSQL_row *row = (PLpgSQL_row *) datum;
                HeapTuple    tup;

                if (!row->rowtupdesc)    /* should not happen */
                    elog(ERROR, "row variable has no tupdesc");
                /* Make sure we have a valid type/typmod setting */
                BlessTupleDesc(row->rowtupdesc);
                oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
                tup = make_tuple_from_row(estate, row, row->rowtupdesc);
                if (tup == NULL)    /* should not happen */
                    elog(ERROR, "row not compatible with its own tupdesc");
                *typeid = row->rowtupdesc->tdtypeid;
                *typetypmod = row->rowtupdesc->tdtypmod;
                *value = HeapTupleGetDatum(tup);
                *isnull = false;
                MemoryContextSwitchTo(oldcontext);
                break;
            }

        case PLPGSQL_DTYPE_REC:
            {
                PLpgSQL_rec *rec = (PLpgSQL_rec *) datum;

                if (!HeapTupleIsValid(rec->tup))
                    ereport(ERROR,
                            (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                             errmsg("record \"%s\" is not assigned yet",
                                    rec->refname),
                             errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
                Assert(rec->tupdesc != NULL);
                /* Make sure we have a valid type/typmod setting */
                BlessTupleDesc(rec->tupdesc);

                oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
                *typeid = rec->tupdesc->tdtypeid;
                *typetypmod = rec->tupdesc->tdtypmod;
                *value = heap_copy_tuple_as_datum(rec->tup, rec->tupdesc);
                *isnull = false;
                MemoryContextSwitchTo(oldcontext);
                break;
            }

        case PLPGSQL_DTYPE_RECFIELD:
            {
                PLpgSQL_recfield *recfield = (PLpgSQL_recfield *) datum;
                PLpgSQL_rec *rec;
                int            fno;

                rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);
                if (!HeapTupleIsValid(rec->tup))
                    ereport(ERROR,
                            (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                             errmsg("record \"%s\" is not assigned yet",
                                    rec->refname),
                             errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
                fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
                if (fno == SPI_ERROR_NOATTRIBUTE)
                    ereport(ERROR,
                            (errcode(ERRCODE_UNDEFINED_COLUMN),
                             errmsg("record \"%s\" has no field \"%s\"",
                                    rec->refname, recfield->fieldname)));
                *typeid = SPI_gettypeid(rec->tupdesc, fno);
                if (fno > 0)
                    *typetypmod = rec->tupdesc->attrs[fno - 1]->atttypmod;
                else
                    *typetypmod = -1;
                *value = SPI_getbinval(rec->tup, rec->tupdesc, fno, isnull);
                break;
            }

        default:
            elog(ERROR, "unrecognized dtype: %d", datum->dtype);
    }
}

/*
 * plpgsql_exec_get_datum_type                Get datatype of a PLpgSQL_datum
 *
 * This is the same logic as in exec_eval_datum, except that it can handle
 * some cases where exec_eval_datum has to fail; specifically, we may have
 * a tupdesc but no row value for a record variable.  (This currently can
 * happen only for a trigger's NEW/OLD records.)
 */
Oid
plpgsql_exec_get_datum_type(PLpgSQL_execstate *estate,
                            PLpgSQL_datum *datum)
{// #lizard forgives
    Oid            typeid;

    switch (datum->dtype)
    {
        case PLPGSQL_DTYPE_VAR:
            {
                PLpgSQL_var *var = (PLpgSQL_var *) datum;

                typeid = var->datatype->typoid;
                break;
            }

        case PLPGSQL_DTYPE_ROW:
            {
                PLpgSQL_row *row = (PLpgSQL_row *) datum;

                if (!row->rowtupdesc)    /* should not happen */
                    elog(ERROR, "row variable has no tupdesc");
                /* Make sure we have a valid type/typmod setting */
                BlessTupleDesc(row->rowtupdesc);
                typeid = row->rowtupdesc->tdtypeid;
                break;
            }

        case PLPGSQL_DTYPE_REC:
            {
                PLpgSQL_rec *rec = (PLpgSQL_rec *) datum;

                if (rec->tupdesc == NULL)
                    ereport(ERROR,
                            (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                             errmsg("record \"%s\" is not assigned yet",
                                    rec->refname),
                             errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
                /* Make sure we have a valid type/typmod setting */
                BlessTupleDesc(rec->tupdesc);
                typeid = rec->tupdesc->tdtypeid;
                break;
            }

        case PLPGSQL_DTYPE_RECFIELD:
            {
                PLpgSQL_recfield *recfield = (PLpgSQL_recfield *) datum;
                PLpgSQL_rec *rec;
                int            fno;

                rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);
                if (rec->tupdesc == NULL)
                    ereport(ERROR,
                            (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                             errmsg("record \"%s\" is not assigned yet",
                                    rec->refname),
                             errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
                fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
                if (fno == SPI_ERROR_NOATTRIBUTE)
                    ereport(ERROR,
                            (errcode(ERRCODE_UNDEFINED_COLUMN),
                             errmsg("record \"%s\" has no field \"%s\"",
                                    rec->refname, recfield->fieldname)));
                typeid = SPI_gettypeid(rec->tupdesc, fno);
                break;
            }

        default:
            elog(ERROR, "unrecognized dtype: %d", datum->dtype);
            typeid = InvalidOid;    /* keep compiler quiet */
            break;
    }

    return typeid;
}

/*
 * plpgsql_exec_get_datum_type_info            Get datatype etc of a PLpgSQL_datum
 *
 * An extended version of plpgsql_exec_get_datum_type, which also retrieves the
 * typmod and collation of the datum.
 */
void
plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
                                 PLpgSQL_datum *datum,
                                 Oid *typeid, int32 *typmod, Oid *collation)
{// #lizard forgives
    switch (datum->dtype)
    {
        case PLPGSQL_DTYPE_VAR:
            {
                PLpgSQL_var *var = (PLpgSQL_var *) datum;

                *typeid = var->datatype->typoid;
                *typmod = var->datatype->atttypmod;
                *collation = var->datatype->collation;
                break;
            }

        case PLPGSQL_DTYPE_ROW:
            {
                PLpgSQL_row *row = (PLpgSQL_row *) datum;

                if (!row->rowtupdesc)    /* should not happen */
                    elog(ERROR, "row variable has no tupdesc");
                /* Make sure we have a valid type/typmod setting */
                BlessTupleDesc(row->rowtupdesc);
                *typeid = row->rowtupdesc->tdtypeid;
                /* do NOT return the mutable typmod of a RECORD variable */
                *typmod = -1;
                /* composite types are never collatable */
                *collation = InvalidOid;
                break;
            }

        case PLPGSQL_DTYPE_REC:
            {
                PLpgSQL_rec *rec = (PLpgSQL_rec *) datum;

                if (rec->tupdesc == NULL)
                    ereport(ERROR,
                            (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                             errmsg("record \"%s\" is not assigned yet",
                                    rec->refname),
                             errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
                /* Make sure we have a valid type/typmod setting */
                BlessTupleDesc(rec->tupdesc);
                *typeid = rec->tupdesc->tdtypeid;
                /* do NOT return the mutable typmod of a RECORD variable */
                *typmod = -1;
                /* composite types are never collatable */
                *collation = InvalidOid;
                break;
            }

        case PLPGSQL_DTYPE_RECFIELD:
            {
                PLpgSQL_recfield *recfield = (PLpgSQL_recfield *) datum;
                PLpgSQL_rec *rec;
                int            fno;

                rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);
                if (rec->tupdesc == NULL)
                    ereport(ERROR,
                            (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                             errmsg("record \"%s\" is not assigned yet",
                                    rec->refname),
                             errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
                fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
                if (fno == SPI_ERROR_NOATTRIBUTE)
                    ereport(ERROR,
                            (errcode(ERRCODE_UNDEFINED_COLUMN),
                             errmsg("record \"%s\" has no field \"%s\"",
                                    rec->refname, recfield->fieldname)));
                *typeid = SPI_gettypeid(rec->tupdesc, fno);
                if (fno > 0)
                    *typmod = rec->tupdesc->attrs[fno - 1]->atttypmod;
                else
                    *typmod = -1;
                if (fno > 0)
                    *collation = rec->tupdesc->attrs[fno - 1]->attcollation;
                else            /* no system column types have collation */
                    *collation = InvalidOid;
                break;
            }

        default:
            elog(ERROR, "unrecognized dtype: %d", datum->dtype);
            *typeid = InvalidOid;    /* keep compiler quiet */
            *typmod = -1;
            *collation = InvalidOid;
            break;
    }
}

/* ----------
 * exec_eval_integer        Evaluate an expression, coerce result to int4
 *
 * Note we do not do exec_eval_cleanup here; the caller must do it at
 * some later point.  (We do this because the caller may be holding the
 * results of other, pass-by-reference, expression evaluations, such as
 * an array value to be subscripted.)
 * ----------
 */
static int
exec_eval_integer(PLpgSQL_execstate *estate,
                  PLpgSQL_expr *expr,
                  bool *isNull)
{
    Datum        exprdatum;
    Oid            exprtypeid;
    int32        exprtypmod;

    exprdatum = exec_eval_expr(estate, expr, isNull, &exprtypeid, &exprtypmod);
    exprdatum = exec_cast_value(estate, exprdatum, isNull,
                                exprtypeid, exprtypmod,
                                INT4OID, -1);
    return DatumGetInt32(exprdatum);
}

/* ----------
 * exec_eval_boolean        Evaluate an expression, coerce result to bool
 *
 * Note we do not do exec_eval_cleanup here; the caller must do it at
 * some later point.
 * ----------
 */
static bool
exec_eval_boolean(PLpgSQL_execstate *estate,
                  PLpgSQL_expr *expr,
                  bool *isNull)
{
    Datum        exprdatum;
    Oid            exprtypeid;
    int32        exprtypmod;

    exprdatum = exec_eval_expr(estate, expr, isNull, &exprtypeid, &exprtypmod);
    exprdatum = exec_cast_value(estate, exprdatum, isNull,
                                exprtypeid, exprtypmod,
                                BOOLOID, -1);
    return DatumGetBool(exprdatum);
}

/* ----------
 * exec_eval_expr            Evaluate an expression and return
 *                    the result Datum, along with data type/typmod.
 *
 * NOTE: caller must do exec_eval_cleanup when done with the Datum.
 * ----------
 */
static Datum
exec_eval_expr(PLpgSQL_execstate *estate,
               PLpgSQL_expr *expr,
               bool *isNull,
               Oid *rettype,
               int32 *rettypmod)
{
    Datum        result = 0;
    int            rc;

    /*
     * If first time through, create a plan for this expression.
     */
    if (expr->plan == NULL)
        exec_prepare_plan(estate, expr, CURSOR_OPT_PARALLEL_OK);

    /*
     * If this is a simple expression, bypass SPI and use the executor
     * directly
     */
    if (exec_eval_simple_expr(estate, expr,
                              &result, isNull, rettype, rettypmod))
        return result;

    /*
     * Else do it the hard way via exec_run_select
     */
    rc = exec_run_select(estate, expr, 2, NULL);
    if (rc != SPI_OK_SELECT)
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("query \"%s\" did not return data", expr->query)));

    /*
     * Check that the expression returns exactly one column...
     */
    if (estate->eval_tuptable->tupdesc->natts != 1)
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg_plural("query \"%s\" returned %d column",
                               "query \"%s\" returned %d columns",
                               estate->eval_tuptable->tupdesc->natts,
                               expr->query,
                               estate->eval_tuptable->tupdesc->natts)));

    /*
     * ... and get the column's datatype.
     */
    *rettype = estate->eval_tuptable->tupdesc->attrs[0]->atttypid;
    *rettypmod = estate->eval_tuptable->tupdesc->attrs[0]->atttypmod;

    /*
     * If there are no rows selected, the result is a NULL of that type.
     */
    if (estate->eval_processed == 0)
    {
        *isNull = true;
        return (Datum) 0;
    }

    /*
     * Check that the expression returned no more than one row.
     */
    if (estate->eval_processed != 1)
        ereport(ERROR,
                (errcode(ERRCODE_CARDINALITY_VIOLATION),
                 errmsg("query \"%s\" returned more than one row",
                        expr->query)));

    /*
     * Return the single result Datum.
     */
    return SPI_getbinval(estate->eval_tuptable->vals[0],
                         estate->eval_tuptable->tupdesc, 1, isNull);
}


/* ----------
 * exec_run_select            Execute a select query
 * ----------
 */
static int
exec_run_select(PLpgSQL_execstate *estate,
                PLpgSQL_expr *expr, long maxtuples, Portal *portalP)
{
    ParamListInfo paramLI;
    int            rc;

    /*
     * On the first call for this expression generate the plan.
     *
     * If we don't need to return a portal, then we're just going to execute
     * the query once, which means it's OK to use a parallel plan, even if the
     * number of rows being fetched is limited.  If we do need to return a
     * portal, the caller might do cursor operations, which parallel query
     * can't support.
     */
    if (expr->plan == NULL)
        exec_prepare_plan(estate, expr,
                          portalP == NULL ? CURSOR_OPT_PARALLEL_OK : 0);

    /*
     * If a portal was requested, put the query into the portal
     */
    if (portalP != NULL)
    {
        /*
         * Set up short-lived ParamListInfo
         */
        paramLI = setup_unshared_param_list(estate, expr);

        *portalP = SPI_cursor_open_with_paramlist(NULL, expr->plan,
                                                  paramLI,
                                                  estate->readonly_func);
        if (*portalP == NULL)
            elog(ERROR, "could not open implicit cursor for query \"%s\": %s",
                 expr->query, SPI_result_code_string(SPI_result));
        exec_eval_cleanup(estate);
        return SPI_OK_CURSOR;
    }

    /*
     * Set up ParamListInfo to pass to executor
     */
    paramLI = setup_param_list(estate, expr);

    /*
     * Execute the query
     */
    rc = SPI_execute_plan_with_paramlist(expr->plan, paramLI,
                                         estate->readonly_func, maxtuples);
    if (rc != SPI_OK_SELECT)
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg("query \"%s\" is not a SELECT", expr->query)));

    /* Save query results for eventual cleanup */
    Assert(estate->eval_tuptable == NULL);
    estate->eval_tuptable = SPI_tuptable;
    estate->eval_processed = SPI_processed;
    estate->eval_lastoid = SPI_lastoid;

    return rc;
}


/*
 * exec_for_query --- execute body of FOR loop for each row from a portal
 *
 * Used by exec_stmt_fors, exec_stmt_forc and exec_stmt_dynfors
 */
static int
exec_for_query(PLpgSQL_execstate *estate, PLpgSQL_stmt_forq *stmt,
               Portal portal, bool prefetch_ok)
{// #lizard forgives
    PLpgSQL_rec *rec = NULL;
    PLpgSQL_row *row = NULL;
    SPITupleTable *tuptab;
    bool        found = false;
    int            rc = PLPGSQL_RC_OK;
    uint64        n;
    long        count;

    /*
     * Determine if we assign to a record or a row
     */
    if (stmt->rec != NULL)
        rec = (PLpgSQL_rec *) (estate->datums[stmt->rec->dno]);
    else if (stmt->row != NULL)
        row = (PLpgSQL_row *) (estate->datums[stmt->row->dno]);
    else
        elog(ERROR, "unsupported target");

    /*
     * Make sure the portal doesn't get closed by the user statements we
     * execute.
     */
    PinPortal(portal);

    /*
     * Fetch the initial tuple(s).  If prefetching is allowed then we grab a
     * few more rows to avoid multiple trips through executor startup
     * overhead.
     */
#define MAX_REMOTE_QUERY_FETCH    200000
    if (IsA(linitial(portal->stmts), PlannedStmt) &&
        (((PlannedStmt *) linitial(portal->stmts))->commandType != CMD_UTILITY) &&
        IsA(((PlannedStmt *) linitial(portal->stmts))->planTree, RemoteQuery))
        count = MAX_REMOTE_QUERY_FETCH;
    else
        count = prefetch_ok ? 10 : 1;

    SPI_cursor_fetch(portal, true, count);
    tuptab = SPI_tuptable;
    n = SPI_processed;

    if (n == MAX_REMOTE_QUERY_FETCH)
        elog(ERROR, "Can fetch only %d tuples via RemoteQuery execution",
                MAX_REMOTE_QUERY_FETCH);

    /*
     * If the query didn't return any rows, set the target to NULL and fall
     * through with found = false.
     */
    if (n == 0)
    {
        exec_move_row(estate, rec, row, NULL, tuptab->tupdesc);
        exec_eval_cleanup(estate);
    }
    else
        found = true;            /* processed at least one tuple */

    /*
     * Now do the loop
     */
    while (n > 0)
    {
        uint64        i;

        for (i = 0; i < n; i++)
        {
            /*
             * Assign the tuple to the target
             */
            exec_move_row(estate, rec, row, tuptab->vals[i], tuptab->tupdesc);
            exec_eval_cleanup(estate);

            /*
             * Execute the statements
             */
            rc = exec_stmts(estate, stmt->body);

            if (rc != PLPGSQL_RC_OK)
            {
                if (rc == PLPGSQL_RC_EXIT)
                {
                    if (estate->exitlabel == NULL)
                    {
                        /* unlabelled exit, so exit the current loop */
                        rc = PLPGSQL_RC_OK;
                    }
                    else if (stmt->label != NULL &&
                             strcmp(stmt->label, estate->exitlabel) == 0)
                    {
                        /* label matches this loop, so exit loop */
                        estate->exitlabel = NULL;
                        rc = PLPGSQL_RC_OK;
                    }

                    /*
                     * otherwise, we processed a labelled exit that does not
                     * match the current statement's label, if any; return
                     * RC_EXIT so that the EXIT continues to recurse upward.
                     */
                }
                else if (rc == PLPGSQL_RC_CONTINUE)
                {
                    if (estate->exitlabel == NULL)
                    {
                        /* unlabelled continue, so re-run the current loop */
                        rc = PLPGSQL_RC_OK;
                        continue;
                    }
                    else if (stmt->label != NULL &&
                             strcmp(stmt->label, estate->exitlabel) == 0)
                    {
                        /* label matches this loop, so re-run loop */
                        estate->exitlabel = NULL;
                        rc = PLPGSQL_RC_OK;
                        continue;
                    }

                    /*
                     * otherwise, we process a labelled continue that does not
                     * match the current statement's label, if any; return
                     * RC_CONTINUE so that the CONTINUE will propagate up the
                     * stack.
                     */
                }

                /*
                 * We're aborting the loop.  Need a goto to get out of two
                 * levels of loop...
                 */
                goto loop_exit;
            }
        }

        SPI_freetuptable(tuptab);

        /*
         * Fetch more tuples.  If prefetching is allowed, grab 50 at a time.
         */
        SPI_cursor_fetch(portal, true, prefetch_ok ? 50 : 1);
        tuptab = SPI_tuptable;
        n = SPI_processed;
    }

loop_exit:

    /*
     * Release last group of tuples (if any)
     */
    SPI_freetuptable(tuptab);

    UnpinPortal(portal);

    /*
     * Set the FOUND variable to indicate the result of executing the loop
     * (namely, whether we looped one or more times). This must be set last so
     * that it does not interfere with the value of the FOUND variable inside
     * the loop processing itself.
     */
    exec_set_found(estate, found);

    return rc;
}


/* ----------
 * exec_eval_simple_expr -        Evaluate a simple expression returning
 *                                a Datum by directly calling ExecEvalExpr().
 *
 * If successful, store results into *result, *isNull, *rettype, *rettypmod
 * and return TRUE.  If the expression cannot be handled by simple evaluation,
 * return FALSE.
 *
 * Because we only store one execution tree for a simple expression, we
 * can't handle recursion cases.  So, if we see the tree is already busy
 * with an evaluation in the current xact, we just return FALSE and let the
 * caller run the expression the hard way.  (Other alternatives such as
 * creating a new tree for a recursive call either introduce memory leaks,
 * or add enough bookkeeping to be doubtful wins anyway.)  Another case that
 * is covered by the expr_simple_in_use test is where a previous execution
 * of the tree was aborted by an error: the tree may contain bogus state
 * so we dare not re-use it.
 *
 * It is possible though unlikely for a simple expression to become non-simple
 * (consider for example redefining a trivial view).  We must handle that for
 * correctness; fortunately it's normally inexpensive to call
 * SPI_plan_get_cached_plan for a simple expression.  We do not consider the
 * other direction (non-simple expression becoming simple) because we'll still
 * give correct results if that happens, and it's unlikely to be worth the
 * cycles to check.
 *
 * Note: if pass-by-reference, the result is in the eval_mcontext.
 * It will be freed when exec_eval_cleanup is done.
 * ----------
 */
static bool
exec_eval_simple_expr(PLpgSQL_execstate *estate,
                      PLpgSQL_expr *expr,
                      Datum *result,
                      bool *isNull,
                      Oid *rettype,
                      int32 *rettypmod)
{// #lizard forgives
    ExprContext *econtext = estate->eval_econtext;
    LocalTransactionId curlxid = MyProc->lxid;
    CachedPlan *cplan;
    ParamListInfo paramLI;
    void       *save_setup_arg;
    MemoryContext oldcontext;

    /*
     * Forget it if expression wasn't simple before.
     */
    if (expr->expr_simple_expr == NULL)
        return false;

    /*
     * If expression is in use in current xact, don't touch it.
     */
    if (expr->expr_simple_in_use && expr->expr_simple_lxid == curlxid)
        return false;

    /*
     * Revalidate cached plan, so that we will notice if it became stale. (We
     * need to hold a refcount while using the plan, anyway.)  If replanning
     * is needed, do that work in the eval_mcontext.
     */
    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
    cplan = SPI_plan_get_cached_plan(expr->plan);
    MemoryContextSwitchTo(oldcontext);

    /*
     * We can't get a failure here, because the number of CachedPlanSources in
     * the SPI plan can't change from what exec_simple_check_plan saw; it's a
     * property of the raw parsetree generated from the query text.
     */
    Assert(cplan != NULL);

    if (cplan->generation != expr->expr_simple_generation)
    {
        /* It got replanned ... is it still simple? */
        exec_simple_recheck_plan(expr, cplan);
        /* better recheck r/w safety, as well */
        if (expr->rwparam >= 0)
            exec_check_rw_parameter(expr, expr->rwparam);
        if (expr->expr_simple_expr == NULL)
        {
            /* Oops, release refcount and fail */
            ReleaseCachedPlan(cplan, true);
            return false;
        }
    }

    /*
     * Pass back previously-determined result type.
     */
    *rettype = expr->expr_simple_type;
    *rettypmod = expr->expr_simple_typmod;

    /*
     * Prepare the expression for execution, if it's not been done already in
     * the current transaction.  (This will be forced to happen if we called
     * exec_simple_recheck_plan above.)
     */
    if (expr->expr_simple_lxid != curlxid)
    {
        oldcontext = MemoryContextSwitchTo(estate->simple_eval_estate->es_query_cxt);
        expr->expr_simple_state = ExecInitExpr(expr->expr_simple_expr, NULL);
        expr->expr_simple_in_use = false;
        expr->expr_simple_lxid = curlxid;
        MemoryContextSwitchTo(oldcontext);
    }

    /*
     * We have to do some of the things SPI_execute_plan would do, in
     * particular advance the snapshot if we are in a non-read-only function.
     * Without this, stable functions within the expression would fail to see
     * updates made so far by our own function.
     */
    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
    if (!estate->readonly_func)
    {
        CommandCounterIncrement();
        PushActiveSnapshot(GetTransactionSnapshot());
    }

    /*
     * Set up ParamListInfo to pass to executor.  We need an unshared list if
     * it's going to include any R/W expanded-object pointer.  For safety,
     * save and restore estate->paramLI->parserSetupArg around our use of the
     * param list.
     */
    save_setup_arg = estate->paramLI->parserSetupArg;

    if (expr->rwparam >= 0)
        paramLI = setup_unshared_param_list(estate, expr);
    else
        paramLI = setup_param_list(estate, expr);

    econtext->ecxt_param_list_info = paramLI;

    /*
     * Mark expression as busy for the duration of the ExecEvalExpr call.
     */
    expr->expr_simple_in_use = true;

    /*
     * Finally we can call the executor to evaluate the expression
     */
    *result = ExecEvalExpr(expr->expr_simple_state,
                           econtext,
                           isNull);

    /* Assorted cleanup */
    expr->expr_simple_in_use = false;

    econtext->ecxt_param_list_info = NULL;

    estate->paramLI->parserSetupArg = save_setup_arg;

    if (!estate->readonly_func)
        PopActiveSnapshot();

    MemoryContextSwitchTo(oldcontext);

    /*
     * Now we can release our refcount on the cached plan.
     */
    ReleaseCachedPlan(cplan, true);

    /*
     * That's it.
     */
    return true;
}


/*
 * Create a ParamListInfo to pass to SPI
 *
 * We share a single ParamListInfo array across all SPI calls made from this
 * estate, except calls creating cursors, which use setup_unshared_param_list
 * (see its comments for reasons why), and calls that pass a R/W expanded
 * object pointer.  A shared array is generally OK since any given slot in
 * the array would need to contain the same current datum value no matter
 * which query or expression we're evaluating; but of course that doesn't
 * hold when a specific variable is being passed as a R/W pointer, because
 * other expressions in the same function probably don't want to do that.
 *
 * Note that paramLI->parserSetupArg points to the specific PLpgSQL_expr
 * being evaluated.  This is not an issue for statement-level callers, but
 * lower-level callers must save and restore estate->paramLI->parserSetupArg
 * just in case there's an active evaluation at an outer call level.
 *
 * The general plan for passing parameters to SPI is that plain VAR datums
 * always have valid images in the shared param list.  This is ensured by
 * assign_simple_var(), which also marks those params as PARAM_FLAG_CONST,
 * allowing the planner to use those values in custom plans.  However, non-VAR
 * datums cannot conveniently be managed that way.  For one thing, they could
 * throw errors (for example "no such record field") and we do not want that
 * to happen in a part of the expression that might never be evaluated at
 * runtime.  For another thing, exec_eval_datum() may return short-lived
 * values stored in the estate's eval_mcontext, which will not necessarily
 * survive to the next SPI operation.  And for a third thing, ROW
 * and RECFIELD datums' values depend on other datums, and we don't have a
 * cheap way to track that.  Therefore, param slots for non-VAR datum types
 * are always reset here and then filled on-demand by plpgsql_param_fetch().
 * We can save a few cycles by not bothering with the reset loop unless at
 * least one such param has actually been filled by plpgsql_param_fetch().
 */
static ParamListInfo
setup_param_list(PLpgSQL_execstate *estate, PLpgSQL_expr *expr)
{
    ParamListInfo paramLI;

    /*
     * We must have created the SPIPlan already (hence, query text has been
     * parsed/analyzed at least once); else we cannot rely on expr->paramnos.
     */
    Assert(expr->plan != NULL);

    /*
     * Expressions with R/W parameters can't use the shared param list.
     */
    Assert(expr->rwparam == -1);

    /*
     * We only need a ParamListInfo if the expression has parameters.  In
     * principle we should test with bms_is_empty(), but we use a not-null
     * test because it's faster.  In current usage bits are never removed from
     * expr->paramnos, only added, so this test is correct anyway.
     */
    if (expr->paramnos)
    {
        /* Use the common ParamListInfo */
        paramLI = estate->paramLI;

        /*
         * If any resettable parameters have been passed to the executor since
         * last time, we need to reset those param slots to "invalid", for the
         * reasons mentioned in the comment above.
         */
        if (estate->params_dirty)
        {
            Bitmapset  *resettable_datums = estate->func->resettable_datums;
            int            dno = -1;

            while ((dno = bms_next_member(resettable_datums, dno)) >= 0)
            {
                ParamExternData *prm = &paramLI->params[dno];

                prm->ptype = InvalidOid;
            }
            estate->params_dirty = false;
        }

        /*
         * Set up link to active expr where the hook functions can find it.
         * Callers must save and restore parserSetupArg if there is any chance
         * that they are interrupting an active use of parameters.
         */
        paramLI->parserSetupArg = (void *) expr;

        /*
         * Allow parameters that aren't needed by this expression to be
         * ignored.
         */
        paramLI->paramMask = expr->paramnos;

        /*
         * Also make sure this is set before parser hooks need it.  There is
         * no need to save and restore, since the value is always correct once
         * set.  (Should be set already, but let's be sure.)
         */
        expr->func = estate->func;
    }
    else
    {
        /*
         * Expression requires no parameters.  Be sure we represent this case
         * as a NULL ParamListInfo, so that plancache.c knows there is no
         * point in a custom plan.
         */
        paramLI = NULL;
    }
    return paramLI;
}

/*
 * Create an unshared, short-lived ParamListInfo to pass to SPI
 *
 * When creating a cursor, we do not use the shared ParamListInfo array
 * but create a short-lived one that will contain only params actually
 * referenced by the query.  The reason for this is that copyParamList() will
 * be used to copy the parameters into cursor-lifespan storage, and we don't
 * want it to copy anything that's not used by the specific cursor; that
 * could result in uselessly copying some large values.
 *
 * We also use this for expressions that are passing a R/W object pointer
 * to some trusted function.  We don't want the R/W pointer to get into the
 * shared param list, where it could get passed to some less-trusted function.
 *
 * The result, if not NULL, is in the estate's eval_mcontext.
 *
 * XXX. Could we use ParamListInfo's new paramMask to avoid creating unshared
 * parameter lists?
 */
static ParamListInfo
setup_unshared_param_list(PLpgSQL_execstate *estate, PLpgSQL_expr *expr)
{
    ParamListInfo paramLI;

    /*
     * We must have created the SPIPlan already (hence, query text has been
     * parsed/analyzed at least once); else we cannot rely on expr->paramnos.
     */
    Assert(expr->plan != NULL);

    /*
     * We only need a ParamListInfo if the expression has parameters.  In
     * principle we should test with bms_is_empty(), but we use a not-null
     * test because it's faster.  In current usage bits are never removed from
     * expr->paramnos, only added, so this test is correct anyway.
     */
    if (expr->paramnos)
    {
        int            dno;

        /* initialize ParamListInfo with one entry per datum, all invalid */
        paramLI = (ParamListInfo)
            eval_mcontext_alloc0(estate,
                                 offsetof(ParamListInfoData, params) +
                                 estate->ndatums * sizeof(ParamExternData));
        paramLI->paramFetch = plpgsql_param_fetch;
        paramLI->paramFetchArg = (void *) estate;
        paramLI->parserSetup = (ParserSetupHook) plpgsql_parser_setup;
        paramLI->parserSetupArg = (void *) expr;
        paramLI->numParams = estate->ndatums;
        paramLI->paramMask = NULL;

        /*
         * Instantiate values for "safe" parameters of the expression.  We
         * could skip this and leave them to be filled by plpgsql_param_fetch;
         * but then the values would not be available for query planning,
         * since the planner doesn't call the paramFetch hook.
         */
        dno = -1;
        while ((dno = bms_next_member(expr->paramnos, dno)) >= 0)
        {
            PLpgSQL_datum *datum = estate->datums[dno];

            if (datum->dtype == PLPGSQL_DTYPE_VAR)
            {
                PLpgSQL_var *var = (PLpgSQL_var *) datum;
                ParamExternData *prm = &paramLI->params[dno];

                if (dno == expr->rwparam)
                    prm->value = var->value;
                else
                    prm->value = MakeExpandedObjectReadOnly(var->value,
                                                            var->isnull,
                                                            var->datatype->typlen);
                prm->isnull = var->isnull;
                prm->pflags = PARAM_FLAG_CONST;
                prm->ptype = var->datatype->typoid;
            }
        }

        /*
         * Also make sure this is set before parser hooks need it.  There is
         * no need to save and restore, since the value is always correct once
         * set.  (Should be set already, but let's be sure.)
         */
        expr->func = estate->func;
    }
    else
    {
        /*
         * Expression requires no parameters.  Be sure we represent this case
         * as a NULL ParamListInfo, so that plancache.c knows there is no
         * point in a custom plan.
         */
        paramLI = NULL;
    }
    return paramLI;
}

/*
 * plpgsql_param_fetch        paramFetch callback for dynamic parameter fetch
 */
static void
plpgsql_param_fetch(ParamListInfo params, int paramid)
{// #lizard forgives
    int            dno;
    PLpgSQL_execstate *estate;
    PLpgSQL_expr *expr;
    PLpgSQL_datum *datum;
    ParamExternData *prm;
    int32        prmtypmod;

    /* paramid's are 1-based, but dnos are 0-based */
    dno = paramid - 1;
    Assert(dno >= 0 && dno < params->numParams);

    /* fetch back the hook data */
    estate = (PLpgSQL_execstate *) params->paramFetchArg;
    expr = (PLpgSQL_expr *) params->parserSetupArg;
    Assert(params->numParams == estate->ndatums);

    /* now we can access the target datum */
    datum = estate->datums[dno];

    /*
     * Since copyParamList() or SerializeParamList() will try to materialize
     * every single parameter slot, it's important to do nothing when asked
     * for a datum that's not supposed to be used by this SQL expression.
     * Otherwise we risk failures in exec_eval_datum(), or copying a lot more
     * data than necessary.
     */
    if (!bms_is_member(dno, expr->paramnos))
        return;

    if (params == estate->paramLI)
    {
        /*
         * We need to mark the shared params array dirty if we're about to
         * evaluate a resettable datum.
         */
        switch (datum->dtype)
        {
            case PLPGSQL_DTYPE_ROW:
            case PLPGSQL_DTYPE_REC:
            case PLPGSQL_DTYPE_RECFIELD:
                estate->params_dirty = true;
                break;

            default:
                break;
        }
    }

    /* OK, evaluate the value and store into the appropriate paramlist slot */
    prm = &params->params[dno];
    exec_eval_datum(estate, datum,
                    &prm->ptype, &prmtypmod,
                    &prm->value, &prm->isnull);
    /* We can always mark params as "const" for executor's purposes */
    prm->pflags = PARAM_FLAG_CONST;

    /*
     * If it's a read/write expanded datum, convert reference to read-only,
     * unless it's safe to pass as read-write.
     */
    if (datum->dtype == PLPGSQL_DTYPE_VAR && dno != expr->rwparam)
        prm->value = MakeExpandedObjectReadOnly(prm->value,
                                                prm->isnull,
                                                ((PLpgSQL_var *) datum)->datatype->typlen);
}


/* ----------
 * exec_move_row            Move one tuple's values into a record or row
 *
 * Since this uses exec_assign_value, caller should eventually call
 * exec_eval_cleanup to prevent long-term memory leaks.
 * ----------
 */
static void
exec_move_row(PLpgSQL_execstate *estate,
              PLpgSQL_rec *rec,
              PLpgSQL_row *row,
              HeapTuple tup, TupleDesc tupdesc)
{// #lizard forgives
    /*
     * Record is simple - just copy the tuple and its descriptor into the
     * record variable
     */
    if (rec != NULL)
    {
        /*
         * Copy input first, just in case it is pointing at variable's value
         */
        if (HeapTupleIsValid(tup))
            tup = heap_copytuple(tup);
        else if (tupdesc)
        {
            /* If we have a tupdesc but no data, form an all-nulls tuple */
            bool       *nulls;

            nulls = (bool *)
                eval_mcontext_alloc(estate, tupdesc->natts * sizeof(bool));
            memset(nulls, true, tupdesc->natts * sizeof(bool));

            tup = heap_form_tuple(tupdesc, NULL, nulls);
        }

        if (tupdesc)
            tupdesc = CreateTupleDescCopy(tupdesc);

        /* Free the old value ... */
        if (rec->freetup)
        {
            heap_freetuple(rec->tup);
            rec->freetup = false;
        }
        if (rec->freetupdesc)
        {
            FreeTupleDesc(rec->tupdesc);
            rec->freetupdesc = false;
        }

        /* ... and install the new */
        if (HeapTupleIsValid(tup))
        {
            rec->tup = tup;
            rec->freetup = true;
        }
        else
            rec->tup = NULL;

        if (tupdesc)
        {
            rec->tupdesc = tupdesc;
            rec->freetupdesc = true;
        }
        else
            rec->tupdesc = NULL;

        return;
    }

    /*
     * Row is a bit more complicated in that we assign the individual
     * attributes of the tuple to the variables the row points to.
     *
     * NOTE: this code used to demand row->nfields ==
     * HeapTupleHeaderGetNatts(tup->t_data), but that's wrong.  The tuple
     * might have more fields than we expected if it's from an
     * inheritance-child table of the current table, or it might have fewer if
     * the table has had columns added by ALTER TABLE. Ignore extra columns
     * and assume NULL for missing columns, the same as heap_getattr would do.
     * We also have to skip over dropped columns in either the source or
     * destination.
     *
     * If we have no tuple data at all, we'll assign NULL to all columns of
     * the row variable.
     */
    if (row != NULL)
    {
        int            td_natts = tupdesc ? tupdesc->natts : 0;
        int            t_natts;
        int            fnum;
        int            anum;

        if (HeapTupleIsValid(tup))
            t_natts = HeapTupleHeaderGetNatts(tup->t_data);
        else
            t_natts = 0;

        anum = 0;
        for (fnum = 0; fnum < row->nfields; fnum++)
        {
            PLpgSQL_var *var;
            Datum        value;
            bool        isnull;
            Oid            valtype;
            int32        valtypmod;

            if (row->varnos[fnum] < 0)
                continue;        /* skip dropped column in row struct */

            var = (PLpgSQL_var *) (estate->datums[row->varnos[fnum]]);

            while (anum < td_natts && tupdesc->attrs[anum]->attisdropped)
                anum++;            /* skip dropped column in tuple */

            if (anum < td_natts)
            {
                if (anum < t_natts)
                    value = SPI_getbinval(tup, tupdesc, anum + 1, &isnull);
                else
                {
                    value = (Datum) 0;
                    isnull = true;
                }
                valtype = tupdesc->attrs[anum]->atttypid;
                valtypmod = tupdesc->attrs[anum]->atttypmod;
                anum++;
            }
            else
            {
                value = (Datum) 0;
                isnull = true;
                valtype = UNKNOWNOID;
                valtypmod = -1;
            }

            exec_assign_value(estate, (PLpgSQL_datum *) var,
                              value, isnull, valtype, valtypmod);
        }

        return;
    }

    elog(ERROR, "unsupported target");
}

/* ----------
 * make_tuple_from_row        Make a tuple from the values of a row object
 *
 * A NULL return indicates rowtype mismatch; caller must raise suitable error
 *
 * The result tuple is freshly palloc'd in caller's context.  Some junk
 * may be left behind in eval_mcontext, too.
 * ----------
 */
static HeapTuple
make_tuple_from_row(PLpgSQL_execstate *estate,
                    PLpgSQL_row *row,
                    TupleDesc tupdesc)
{
    int            natts = tupdesc->natts;
    HeapTuple    tuple;
    Datum       *dvalues;
    bool       *nulls;
    int            i;

    if (natts != row->nfields)
        return NULL;

    dvalues = (Datum *) eval_mcontext_alloc0(estate, natts * sizeof(Datum));
    nulls = (bool *) eval_mcontext_alloc(estate, natts * sizeof(bool));

    for (i = 0; i < natts; i++)
    {
        Oid            fieldtypeid;
        int32        fieldtypmod;

        if (tupdesc->attrs[i]->attisdropped)
        {
            nulls[i] = true;    /* leave the column as null */
            continue;
        }
        if (row->varnos[i] < 0) /* should not happen */
            elog(ERROR, "dropped rowtype entry for non-dropped column");

        exec_eval_datum(estate, estate->datums[row->varnos[i]],
                        &fieldtypeid, &fieldtypmod,
                        &dvalues[i], &nulls[i]);
        if (fieldtypeid != tupdesc->attrs[i]->atttypid)
            return NULL;
        /* XXX should we insist on typmod match, too? */
    }

    tuple = heap_form_tuple(tupdesc, dvalues, nulls);

    return tuple;
}

/* ----------
 * get_tuple_from_datum        extract a tuple from a composite Datum
 *
 * Returns a HeapTuple, freshly palloc'd in caller's context.
 *
 * Note: it's caller's responsibility to be sure value is of composite type.
 * ----------
 */
static HeapTuple
get_tuple_from_datum(Datum value)
{
    HeapTupleHeader td = DatumGetHeapTupleHeader(value);
    HeapTupleData tmptup;

    /* Build a temporary HeapTuple control structure */
    tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
    ItemPointerSetInvalid(&(tmptup.t_self));
    tmptup.t_tableOid = InvalidOid;
    tmptup.t_data = td;
	tmptup.t_xc_node_id = InvalidOid;

    /* Build a copy and return it */
    return heap_copytuple(&tmptup);
}

/* ----------
 * get_tupdesc_from_datum    get a tuple descriptor for a composite Datum
 *
 * Returns a pointer to the TupleDesc of the tuple's rowtype.
 * Caller is responsible for calling ReleaseTupleDesc when done with it.
 *
 * Note: it's caller's responsibility to be sure value is of composite type.
 * ----------
 */
static TupleDesc
get_tupdesc_from_datum(Datum value)
{
    HeapTupleHeader td = DatumGetHeapTupleHeader(value);
    Oid            tupType;
    int32        tupTypmod;

    /* Extract rowtype info and find a tupdesc */
    tupType = HeapTupleHeaderGetTypeId(td);
    tupTypmod = HeapTupleHeaderGetTypMod(td);
    return lookup_rowtype_tupdesc(tupType, tupTypmod);
}

/* ----------
 * exec_move_row_from_datum        Move a composite Datum into a record or row
 *
 * This is equivalent to get_tuple_from_datum() followed by exec_move_row(),
 * but we avoid constructing an intermediate physical copy of the tuple.
 * ----------
 */
static void
exec_move_row_from_datum(PLpgSQL_execstate *estate,
                         PLpgSQL_rec *rec,
                         PLpgSQL_row *row,
                         Datum value)
{
    HeapTupleHeader td = DatumGetHeapTupleHeader(value);
    Oid            tupType;
    int32        tupTypmod;
    TupleDesc    tupdesc;
    HeapTupleData tmptup;

    /* Extract rowtype info and find a tupdesc */
    tupType = HeapTupleHeaderGetTypeId(td);
    tupTypmod = HeapTupleHeaderGetTypMod(td);
    tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);

    /* Build a temporary HeapTuple control structure */
    tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
    ItemPointerSetInvalid(&(tmptup.t_self));
    tmptup.t_tableOid = InvalidOid;
    tmptup.t_data = td;

#ifdef PGXC
    tmptup.t_xc_node_id = 0;
#endif

    /* Do the move */
    exec_move_row(estate, rec, row, &tmptup, tupdesc);

    /* Release tupdesc usage count */
    ReleaseTupleDesc(tupdesc);
}

/* ----------
 * convert_value_to_string            Convert a non-null Datum to C string
 *
 * Note: the result is in the estate's eval_mcontext, and will be cleared
 * by the next exec_eval_cleanup() call.  The invoked output function might
 * leave additional cruft there as well, so just pfree'ing the result string
 * would not be enough to avoid memory leaks if we did not do it like this.
 * In most usages the Datum being passed in is also in that context (if
 * pass-by-reference) and so an exec_eval_cleanup() call is needed anyway.
 *
 * Note: not caching the conversion function lookup is bad for performance.
 * However, this function isn't currently used in any places where an extra
 * catalog lookup or two seems like a big deal.
 * ----------
 */
static char *
convert_value_to_string(PLpgSQL_execstate *estate, Datum value, Oid valtype)
{
    char       *result;
    MemoryContext oldcontext;
    Oid            typoutput;
    bool        typIsVarlena;

    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
    getTypeOutputInfo(valtype, &typoutput, &typIsVarlena);
    result = OidOutputFunctionCall(typoutput, value);
    MemoryContextSwitchTo(oldcontext);

    return result;
}

/* ----------
 * exec_cast_value            Cast a value if required
 *
 * Note that *isnull is an input and also an output parameter.  While it's
 * unlikely that a cast operation would produce null from non-null or vice
 * versa, that could happen in principle.
 *
 * Note: the estate's eval_mcontext is used for temporary storage, and may
 * also contain the result Datum if we have to do a conversion to a pass-
 * by-reference data type.  Be sure to do an exec_eval_cleanup() call when
 * done with the result.
 * ----------
 */
static Datum
exec_cast_value(PLpgSQL_execstate *estate,
                Datum value, bool *isnull,
                Oid valtype, int32 valtypmod,
                Oid reqtype, int32 reqtypmod)
{
    /*
     * If the type of the given value isn't what's requested, convert it.
     */
    if (valtype != reqtype ||
        (valtypmod != reqtypmod && reqtypmod != -1))
    {
        plpgsql_CastHashEntry *cast_entry;

        cast_entry = get_cast_hashentry(estate,
                                        valtype, valtypmod,
                                        reqtype, reqtypmod);
        if (cast_entry)
        {
            ExprContext *econtext = estate->eval_econtext;
            MemoryContext oldcontext;

            oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));

            econtext->caseValue_datum = value;
            econtext->caseValue_isNull = *isnull;

            cast_entry->cast_in_use = true;

            value = ExecEvalExpr(cast_entry->cast_exprstate, econtext,
                                 isnull);

            cast_entry->cast_in_use = false;

            MemoryContextSwitchTo(oldcontext);
        }
    }

    return value;
}

/* ----------
 * get_cast_hashentry            Look up how to perform a type cast
 *
 * Returns a plpgsql_CastHashEntry if an expression has to be evaluated,
 * or NULL if the cast is a mere no-op relabeling.  If there's work to be
 * done, the cast_exprstate field contains an expression evaluation tree
 * based on a CaseTestExpr input, and the cast_in_use field should be set
 * TRUE while executing it.
 * ----------
 */
static plpgsql_CastHashEntry *
get_cast_hashentry(PLpgSQL_execstate *estate,
                   Oid srctype, int32 srctypmod,
                   Oid dsttype, int32 dsttypmod)
{// #lizard forgives
    plpgsql_CastHashKey cast_key;
    plpgsql_CastHashEntry *cast_entry;
    bool        found;
    LocalTransactionId curlxid;
    MemoryContext oldcontext;

    /* Look for existing entry */
    cast_key.srctype = srctype;
    cast_key.dsttype = dsttype;
    cast_key.srctypmod = srctypmod;
    cast_key.dsttypmod = dsttypmod;
    cast_entry = (plpgsql_CastHashEntry *) hash_search(estate->cast_hash,
                                                       (void *) &cast_key,
                                                       HASH_FIND, NULL);

    if (cast_entry == NULL)
    {
        /* We've not looked up this coercion before */
        Node       *cast_expr;
        CaseTestExpr *placeholder;

        /*
         * Since we could easily fail (no such coercion), construct a
         * temporary coercion expression tree in the short-lived
         * eval_mcontext, then if successful copy it to cast_hash_context.
         */
        oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));

        /*
         * We use a CaseTestExpr as the base of the coercion tree, since it's
         * very cheap to insert the source value for that.
         */
        placeholder = makeNode(CaseTestExpr);
        placeholder->typeId = srctype;
        placeholder->typeMod = srctypmod;
        placeholder->collation = get_typcollation(srctype);

        /*
         * Apply coercion.  We use ASSIGNMENT coercion because that's the
         * closest match to plpgsql's historical behavior; in particular,
         * EXPLICIT coercion would allow silent truncation to a destination
         * varchar/bpchar's length, which we do not want.
         *
         * If source type is UNKNOWN, coerce_to_target_type will fail (it only
         * expects to see that for Const input nodes), so don't call it; we'll
         * apply CoerceViaIO instead.  Likewise, it doesn't currently work for
         * coercing RECORD to some other type, so skip for that too.
         */
        if (srctype == UNKNOWNOID || srctype == RECORDOID)
            cast_expr = NULL;
        else
            cast_expr = coerce_to_target_type(NULL,
                                              (Node *) placeholder, srctype,
                                              dsttype, dsttypmod,
                                              COERCION_ASSIGNMENT,
                                              COERCE_IMPLICIT_CAST,
                                              -1);

        /*
         * If there's no cast path according to the parser, fall back to using
         * an I/O coercion; this is semantically dubious but matches plpgsql's
         * historical behavior.  We would need something of the sort for
         * UNKNOWN literals in any case.
         */
        if (cast_expr == NULL)
        {
            CoerceViaIO *iocoerce = makeNode(CoerceViaIO);

            iocoerce->arg = (Expr *) placeholder;
            iocoerce->resulttype = dsttype;
            iocoerce->resultcollid = InvalidOid;
            iocoerce->coerceformat = COERCE_IMPLICIT_CAST;
            iocoerce->location = -1;
            cast_expr = (Node *) iocoerce;
            if (dsttypmod != -1)
                cast_expr = coerce_to_target_type(NULL,
                                                  cast_expr, dsttype,
                                                  dsttype, dsttypmod,
                                                  COERCION_ASSIGNMENT,
                                                  COERCE_IMPLICIT_CAST,
                                                  -1);
        }

        /* Note: we don't bother labeling the expression tree with collation */

        /* Detect whether we have a no-op (RelabelType) coercion */
        if (IsA(cast_expr, RelabelType) &&
            ((RelabelType *) cast_expr)->arg == (Expr *) placeholder)
            cast_expr = NULL;

        if (cast_expr)
        {
            /* ExecInitExpr assumes we've planned the expression */
            cast_expr = (Node *) expression_planner((Expr *) cast_expr);

            /* Now copy the tree into cast_hash_context */
            MemoryContextSwitchTo(estate->cast_hash_context);

            cast_expr = copyObject(cast_expr);
        }

        MemoryContextSwitchTo(oldcontext);

        /* Now we can fill in a hashtable entry. */
        cast_entry = (plpgsql_CastHashEntry *) hash_search(estate->cast_hash,
                                                           (void *) &cast_key,
                                                           HASH_ENTER, &found);
        Assert(!found);            /* wasn't there a moment ago */
        cast_entry->cast_expr = (Expr *) cast_expr;
        cast_entry->cast_exprstate = NULL;
        cast_entry->cast_in_use = false;
        cast_entry->cast_lxid = InvalidLocalTransactionId;
    }

    /* Done if we have determined that this is a no-op cast. */
    if (cast_entry->cast_expr == NULL)
        return NULL;

    /*
     * Prepare the expression for execution, if it's not been done already in
     * the current transaction; also, if it's marked busy in the current
     * transaction, abandon that expression tree and build a new one, so as to
     * avoid potential problems with recursive cast expressions and failed
     * executions.  (We will leak some memory intra-transaction if that
     * happens a lot, but we don't expect it to.)  It's okay to update the
     * hash table with the new tree because all plpgsql functions within a
     * given transaction share the same simple_eval_estate.  (Well, regular
     * functions do; DO blocks have private simple_eval_estates, and private
     * cast hash tables to go with them.)
     */
    curlxid = MyProc->lxid;
    if (cast_entry->cast_lxid != curlxid || cast_entry->cast_in_use)
    {
        oldcontext = MemoryContextSwitchTo(estate->simple_eval_estate->es_query_cxt);
        cast_entry->cast_exprstate = ExecInitExpr(cast_entry->cast_expr, NULL);
        cast_entry->cast_in_use = false;
        cast_entry->cast_lxid = curlxid;
        MemoryContextSwitchTo(oldcontext);
    }

    return cast_entry;
}

/* ----------
 * exec_simple_check_node -        Recursively check if an expression
 *                                is made only of simple things we can
 *                                hand out directly to ExecEvalExpr()
 *                                instead of calling SPI.
 * ----------
 */
static bool
exec_simple_check_node(Node *node)
{// #lizard forgives
    if (node == NULL)
        return TRUE;

    switch (nodeTag(node))
    {
        case T_Const:
            return TRUE;

        case T_Param:
            return TRUE;

        case T_ArrayRef:
            {
                ArrayRef   *expr = (ArrayRef *) node;

                if (!exec_simple_check_node((Node *) expr->refupperindexpr))
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->reflowerindexpr))
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->refexpr))
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->refassgnexpr))
                    return FALSE;

                return TRUE;
            }

        case T_FuncExpr:
            {
                FuncExpr   *expr = (FuncExpr *) node;

                if (expr->funcretset)
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_OpExpr:
            {
                OpExpr       *expr = (OpExpr *) node;

                if (expr->opretset)
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_DistinctExpr:
            {
                DistinctExpr *expr = (DistinctExpr *) node;

                if (expr->opretset)
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_NullIfExpr:
            {
                NullIfExpr *expr = (NullIfExpr *) node;

                if (expr->opretset)
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_ScalarArrayOpExpr:
            {
                ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) node;

                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_BoolExpr:
            {
                BoolExpr   *expr = (BoolExpr *) node;

                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_FieldSelect:
            return exec_simple_check_node((Node *) ((FieldSelect *) node)->arg);

        case T_FieldStore:
            {
                FieldStore *expr = (FieldStore *) node;

                if (!exec_simple_check_node((Node *) expr->arg))
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->newvals))
                    return FALSE;

                return TRUE;
            }

        case T_RelabelType:
            return exec_simple_check_node((Node *) ((RelabelType *) node)->arg);

        case T_CoerceViaIO:
            return exec_simple_check_node((Node *) ((CoerceViaIO *) node)->arg);

        case T_ArrayCoerceExpr:
            return exec_simple_check_node((Node *) ((ArrayCoerceExpr *) node)->arg);

        case T_ConvertRowtypeExpr:
            return exec_simple_check_node((Node *) ((ConvertRowtypeExpr *) node)->arg);

        case T_CaseExpr:
            {
                CaseExpr   *expr = (CaseExpr *) node;

                if (!exec_simple_check_node((Node *) expr->arg))
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->defresult))
                    return FALSE;

                return TRUE;
            }

        case T_CaseWhen:
            {
                CaseWhen   *when = (CaseWhen *) node;

                if (!exec_simple_check_node((Node *) when->expr))
                    return FALSE;
                if (!exec_simple_check_node((Node *) when->result))
                    return FALSE;

                return TRUE;
            }

        case T_CaseTestExpr:
            return TRUE;

        case T_ArrayExpr:
            {
                ArrayExpr  *expr = (ArrayExpr *) node;

                if (!exec_simple_check_node((Node *) expr->elements))
                    return FALSE;

                return TRUE;
            }

        case T_RowExpr:
            {
                RowExpr    *expr = (RowExpr *) node;

                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_RowCompareExpr:
            {
                RowCompareExpr *expr = (RowCompareExpr *) node;

                if (!exec_simple_check_node((Node *) expr->largs))
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->rargs))
                    return FALSE;

                return TRUE;
            }

        case T_CoalesceExpr:
            {
                CoalesceExpr *expr = (CoalesceExpr *) node;

                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_MinMaxExpr:
            {
                MinMaxExpr *expr = (MinMaxExpr *) node;

                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_SQLValueFunction:
            return TRUE;

        case T_XmlExpr:
            {
                XmlExpr    *expr = (XmlExpr *) node;

                if (!exec_simple_check_node((Node *) expr->named_args))
                    return FALSE;
                if (!exec_simple_check_node((Node *) expr->args))
                    return FALSE;

                return TRUE;
            }

        case T_NullTest:
            return exec_simple_check_node((Node *) ((NullTest *) node)->arg);

        case T_BooleanTest:
            return exec_simple_check_node((Node *) ((BooleanTest *) node)->arg);

        case T_CoerceToDomain:
            return exec_simple_check_node((Node *) ((CoerceToDomain *) node)->arg);

        case T_CoerceToDomainValue:
            return TRUE;

        case T_List:
            {
                List       *expr = (List *) node;
                ListCell   *l;

                foreach(l, expr)
                {
                    if (!exec_simple_check_node(lfirst(l)))
                        return FALSE;
                }

                return TRUE;
            }

        default:
            return FALSE;
    }
}


/* ----------
 * exec_simple_check_plan -        Check if a plan is simple enough to
 *                                be evaluated by ExecEvalExpr() instead
 *                                of SPI.
 * ----------
 */
static void
exec_simple_check_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr)
{// #lizard forgives
    List       *plansources;
    CachedPlanSource *plansource;
    Query       *query;
    CachedPlan *cplan;
    MemoryContext oldcontext;

    /*
     * Initialize to "not simple", and remember the plan generation number we
     * last checked.  (If we don't get as far as obtaining a plan to check, we
     * just leave expr_simple_generation set to 0.)
     */
    expr->expr_simple_expr = NULL;
    expr->expr_simple_generation = 0;

    /*
     * We can only test queries that resulted in exactly one CachedPlanSource
     */
    plansources = SPI_plan_get_plan_sources(expr->plan);
    if (list_length(plansources) != 1)
        return;
    plansource = (CachedPlanSource *) linitial(plansources);

    /*
     * Do some checking on the analyzed-and-rewritten form of the query. These
     * checks are basically redundant with the tests in
     * exec_simple_recheck_plan, but the point is to avoid building a plan if
     * possible.  Since this function is only called immediately after
     * creating the CachedPlanSource, we need not worry about the query being
     * stale.
     */

    /*
     * 1. There must be one single querytree.
     */
    if (list_length(plansource->query_list) != 1)
        return;
    query = (Query *) linitial(plansource->query_list);

    /*
     * 2. It must be a plain SELECT query without any input tables
     */
    if (!IsA(query, Query))
        return;
    if (query->commandType != CMD_SELECT)
        return;
    if (query->rtable != NIL)
        return;

    /*
     * 3. Can't have any subplans, aggregates, qual clauses either
     */
    if (query->hasAggs ||
        query->hasWindowFuncs ||
        query->hasTargetSRFs ||
        query->hasSubLinks ||
        query->hasForUpdate ||
        query->cteList ||
        query->jointree->quals ||
        query->groupClause ||
        query->havingQual ||
        query->windowClause ||
        query->distinctClause ||
        query->sortClause ||
        query->limitOffset ||
        query->limitCount ||
        query->setOperations)
        return;

    /*
     * 4. The query must have a single attribute as result
     */
    if (list_length(query->targetList) != 1)
        return;

    /*
     * OK, it seems worth constructing a plan for more careful checking.
     *
     * Get the generic plan for the query.  If replanning is needed, do that
     * work in the eval_mcontext.
     */
    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
    cplan = SPI_plan_get_cached_plan(expr->plan);
    MemoryContextSwitchTo(oldcontext);

    /* Can't fail, because we checked for a single CachedPlanSource above */
    Assert(cplan != NULL);

    /* Share the remaining work with recheck code path */
    exec_simple_recheck_plan(expr, cplan);

    /* Release our plan refcount */
    ReleaseCachedPlan(cplan, true);
}

/*
 * exec_simple_recheck_plan --- check for simple plan once we have CachedPlan
 */
static void
exec_simple_recheck_plan(PLpgSQL_expr *expr, CachedPlan *cplan)
{// #lizard forgives
    PlannedStmt *stmt;
    Plan       *plan;
    TargetEntry *tle;

    /*
     * Initialize to "not simple", and remember the plan generation number we
     * last checked.
     */
    expr->expr_simple_expr = NULL;
    expr->expr_simple_generation = cplan->generation;

    /*
     * 1. There must be one single plantree
     */
    if (list_length(cplan->stmt_list) != 1)
        return;
    stmt = linitial_node(PlannedStmt, cplan->stmt_list);

    /*
     * 2. It must be a RESULT plan --> no scan's required
     */
    if (stmt->commandType != CMD_SELECT)
        return;
    plan = stmt->planTree;
    if (!IsA(plan, Result))
        return;

    /*
     * 3. Can't have any subplan or qual clause, either
     */
    if (plan->lefttree != NULL ||
        plan->righttree != NULL ||
        plan->initPlan != NULL ||
        plan->qual != NULL ||
        ((Result *) plan)->resconstantqual != NULL)
        return;

    /*
     * 4. The plan must have a single attribute as result
     */
    if (list_length(plan->targetlist) != 1)
        return;

    tle = (TargetEntry *) linitial(plan->targetlist);

    /*
     * 5. Check that all the nodes in the expression are non-scary.
     */
    if (!exec_simple_check_node((Node *) tle->expr))
        return;

    /*
     * Yes - this is a simple expression.  Mark it as such, and initialize
     * state to "not valid in current transaction".
     */
    expr->expr_simple_expr = tle->expr;
    expr->expr_simple_state = NULL;
    expr->expr_simple_in_use = false;
    expr->expr_simple_lxid = InvalidLocalTransactionId;
    /* Also stash away the expression result type */
    expr->expr_simple_type = exprType((Node *) tle->expr);
    expr->expr_simple_typmod = exprTypmod((Node *) tle->expr);
}

/*
 * exec_check_rw_parameter --- can we pass expanded object as read/write param?
 *
 * If we have an assignment like "x := array_append(x, foo)" in which the
 * top-level function is trusted not to corrupt its argument in case of an
 * error, then when x has an expanded object as value, it is safe to pass the
 * value as a read/write pointer and let the function modify the value
 * in-place.
 *
 * This function checks for a safe expression, and sets expr->rwparam to the
 * dno of the target variable (x) if safe, or -1 if not safe.
 */
static void
exec_check_rw_parameter(PLpgSQL_expr *expr, int target_dno)
{// #lizard forgives
    Oid            funcid;
    List       *fargs;
    ListCell   *lc;

    /* Assume unsafe */
    expr->rwparam = -1;

    /*
     * If the expression isn't simple, there's no point in trying to optimize
     * (because the exec_run_select code path will flatten any expanded result
     * anyway).  Even without that, this seems like a good safety restriction.
     */
    if (expr->expr_simple_expr == NULL)
        return;

    /*
     * If target variable isn't referenced by expression, no need to look
     * further.
     */
    if (!bms_is_member(target_dno, expr->paramnos))
        return;

    /*
     * Top level of expression must be a simple FuncExpr or OpExpr.
     */
    if (IsA(expr->expr_simple_expr, FuncExpr))
    {
        FuncExpr   *fexpr = (FuncExpr *) expr->expr_simple_expr;

        funcid = fexpr->funcid;
        fargs = fexpr->args;
    }
    else if (IsA(expr->expr_simple_expr, OpExpr))
    {
        OpExpr       *opexpr = (OpExpr *) expr->expr_simple_expr;

        funcid = opexpr->opfuncid;
        fargs = opexpr->args;
    }
    else
        return;

    /*
     * The top-level function must be one that we trust to be "safe".
     * Currently we hard-wire the list, but it would be very desirable to
     * allow extensions to mark their functions as safe ...
     */
    if (!(funcid == F_ARRAY_APPEND ||
          funcid == F_ARRAY_PREPEND))
        return;

    /*
     * The target variable (in the form of a Param) must only appear as a
     * direct argument of the top-level function.
     */
    foreach(lc, fargs)
    {
        Node       *arg = (Node *) lfirst(lc);

        /* A Param is OK, whether it's the target variable or not */
        if (arg && IsA(arg, Param))
            continue;
        /* Otherwise, argument expression must not reference target */
        if (contains_target_param(arg, &target_dno))
            return;
    }

    /* OK, we can pass target as a read-write parameter */
    expr->rwparam = target_dno;
}

/*
 * Recursively check for a Param referencing the target variable
 */
static bool
contains_target_param(Node *node, int *target_dno)
{
    if (node == NULL)
        return false;
    if (IsA(node, Param))
    {
        Param       *param = (Param *) node;

        if (param->paramkind == PARAM_EXTERN &&
            param->paramid == *target_dno + 1)
            return true;
        return false;
    }
    return expression_tree_walker(node, contains_target_param,
                                  (void *) target_dno);
}

/* ----------
 * exec_set_found            Set the global found variable to true/false
 * ----------
 */
static void
exec_set_found(PLpgSQL_execstate *estate, bool state)
{
    PLpgSQL_var *var;

    var = (PLpgSQL_var *) (estate->datums[estate->found_varno]);
    assign_simple_var(estate, var, BoolGetDatum(state), false, false);
}

/*
 * plpgsql_create_econtext --- create an eval_econtext for the current function
 *
 * We may need to create a new shared_simple_eval_estate too, if there's not
 * one already for the current transaction.  The EState will be cleaned up at
 * transaction end.
 */
static void
plpgsql_create_econtext(PLpgSQL_execstate *estate)
{
    SimpleEcontextStackEntry *entry;

    /*
     * Create an EState for evaluation of simple expressions, if there's not
     * one already in the current transaction.  The EState is made a child of
     * TopTransactionContext so it will have the right lifespan.
     *
     * Note that this path is never taken when executing a DO block; the
     * required EState was already made by plpgsql_inline_handler.
     */
    if (estate->simple_eval_estate == NULL)
    {
        MemoryContext oldcontext;

        Assert(shared_simple_eval_estate == NULL);
        oldcontext = MemoryContextSwitchTo(TopTransactionContext);
        shared_simple_eval_estate = CreateExecutorState();
        estate->simple_eval_estate = shared_simple_eval_estate;
        MemoryContextSwitchTo(oldcontext);
    }

    /*
     * Create a child econtext for the current function.
     */
    estate->eval_econtext = CreateExprContext(estate->simple_eval_estate);

    /*
     * Make a stack entry so we can clean up the econtext at subxact end.
     * Stack entries are kept in TopTransactionContext for simplicity.
     */
    entry = (SimpleEcontextStackEntry *)
        MemoryContextAlloc(TopTransactionContext,
                           sizeof(SimpleEcontextStackEntry));

    entry->stack_econtext = estate->eval_econtext;
    entry->xact_subxid = GetCurrentSubTransactionId();

    entry->next = simple_econtext_stack;
    simple_econtext_stack = entry;
}

/*
 * plpgsql_destroy_econtext --- destroy function's econtext
 *
 * We check that it matches the top stack entry, and destroy the stack
 * entry along with the context.
 */
static void
plpgsql_destroy_econtext(PLpgSQL_execstate *estate)
{
    SimpleEcontextStackEntry *next;

    Assert(simple_econtext_stack != NULL);
    Assert(simple_econtext_stack->stack_econtext == estate->eval_econtext);

    next = simple_econtext_stack->next;
    pfree(simple_econtext_stack);
    simple_econtext_stack = next;

    FreeExprContext(estate->eval_econtext, true);
    estate->eval_econtext = NULL;
}

/*
 * plpgsql_xact_cb --- post-transaction-commit-or-abort cleanup
 *
 * If a simple-expression EState was created in the current transaction,
 * it has to be cleaned up.
 */
void
plpgsql_xact_cb(XactEvent event, void *arg)
{
    /*
     * If we are doing a clean transaction shutdown, free the EState (so that
     * any remaining resources will be released correctly). In an abort, we
     * expect the regular abort recovery procedures to release everything of
     * interest.
     */
    if (event == XACT_EVENT_COMMIT || event == XACT_EVENT_PREPARE)
    {
        /* Shouldn't be any econtext stack entries left at commit */
        Assert(simple_econtext_stack == NULL);

        if (shared_simple_eval_estate)
            FreeExecutorState(shared_simple_eval_estate);
        shared_simple_eval_estate = NULL;
    }
    else if (event == XACT_EVENT_ABORT)
    {
        simple_econtext_stack = NULL;
        shared_simple_eval_estate = NULL;
    }
}

/*
 * plpgsql_subxact_cb --- post-subtransaction-commit-or-abort cleanup
 *
 * Make sure any simple-expression econtexts created in the current
 * subtransaction get cleaned up.  We have to do this explicitly because
 * no other code knows which econtexts belong to which level of subxact.
 */
void
plpgsql_subxact_cb(SubXactEvent event, SubTransactionId mySubid,
                   SubTransactionId parentSubid, void *arg)
{
    if (event == SUBXACT_EVENT_COMMIT_SUB || event == SUBXACT_EVENT_ABORT_SUB)
    {
        while (simple_econtext_stack != NULL &&
               simple_econtext_stack->xact_subxid == mySubid)
        {
            SimpleEcontextStackEntry *next;

            FreeExprContext(simple_econtext_stack->stack_econtext,
                            (event == SUBXACT_EVENT_COMMIT_SUB));
            next = simple_econtext_stack->next;
            pfree(simple_econtext_stack);
            simple_econtext_stack = next;
        }
    }
}

/*
 * assign_simple_var --- assign a new value to any VAR datum.
 *
 * This should be the only mechanism for assignment to simple variables,
 * lest we forget to update the paramLI image.
 */
static void
assign_simple_var(PLpgSQL_execstate *estate, PLpgSQL_var *var,
                  Datum newvalue, bool isnull, bool freeable)
{
    ParamExternData *prm;

    Assert(var->dtype == PLPGSQL_DTYPE_VAR);
    /* Free the old value if needed */
    if (var->freeval)
    {
        if (DatumIsReadWriteExpandedObject(var->value,
                                           var->isnull,
                                           var->datatype->typlen))
            DeleteExpandedObject(var->value);
        else
            pfree(DatumGetPointer(var->value));
    }
    /* Assign new value to datum */
    var->value = newvalue;
    var->isnull = isnull;
    var->freeval = freeable;
    /* And update the image in the common parameter list */
    prm = &estate->paramLI->params[var->dno];
    prm->value = MakeExpandedObjectReadOnly(newvalue,
                                            isnull,
                                            var->datatype->typlen);
    prm->isnull = isnull;
    /* these might be set already, but let's be sure */
    prm->pflags = PARAM_FLAG_CONST;
    prm->ptype = var->datatype->typoid;
}

/*
 * free old value of a text variable and assign new value from C string
 */
static void
assign_text_var(PLpgSQL_execstate *estate, PLpgSQL_var *var, const char *str)
{
    assign_simple_var(estate, var, CStringGetTextDatum(str), false, true);
}

/*
 * exec_eval_using_params --- evaluate params of USING clause
 *
 * The result data structure is created in the stmt_mcontext, and should
 * be freed by resetting that context.
 */
static PreparedParamsData *
exec_eval_using_params(PLpgSQL_execstate *estate, List *params)
{
    PreparedParamsData *ppd;
    MemoryContext stmt_mcontext = get_stmt_mcontext(estate);
    int            nargs;
    int            i;
    ListCell   *lc;

    ppd = (PreparedParamsData *)
        MemoryContextAlloc(stmt_mcontext, sizeof(PreparedParamsData));
    nargs = list_length(params);

    ppd->nargs = nargs;
    ppd->types = (Oid *)
        MemoryContextAlloc(stmt_mcontext, nargs * sizeof(Oid));
    ppd->values = (Datum *)
        MemoryContextAlloc(stmt_mcontext, nargs * sizeof(Datum));
    ppd->nulls = (char *)
        MemoryContextAlloc(stmt_mcontext, nargs * sizeof(char));

    i = 0;
    foreach(lc, params)
    {
        PLpgSQL_expr *param = (PLpgSQL_expr *) lfirst(lc);
        bool        isnull;
        int32        ppdtypmod;
        MemoryContext oldcontext;

        ppd->values[i] = exec_eval_expr(estate, param,
                                        &isnull,
                                        &ppd->types[i],
                                        &ppdtypmod);
        ppd->nulls[i] = isnull ? 'n' : ' ';

        oldcontext = MemoryContextSwitchTo(stmt_mcontext);

        if (ppd->types[i] == UNKNOWNOID)
        {
            /*
             * Treat 'unknown' parameters as text, since that's what most
             * people would expect. SPI_execute_with_args can coerce unknown
             * constants in a more intelligent way, but not unknown Params.
             * This code also takes care of copying into the right context.
             * Note we assume 'unknown' has the representation of C-string.
             */
            ppd->types[i] = TEXTOID;
            if (!isnull)
                ppd->values[i] = CStringGetTextDatum(DatumGetCString(ppd->values[i]));
        }
        /* pass-by-ref non null values must be copied into stmt_mcontext */
        else if (!isnull)
        {
            int16        typLen;
            bool        typByVal;

            get_typlenbyval(ppd->types[i], &typLen, &typByVal);
            if (!typByVal)
                ppd->values[i] = datumCopy(ppd->values[i], typByVal, typLen);
        }

        MemoryContextSwitchTo(oldcontext);

        exec_eval_cleanup(estate);

        i++;
    }

    return ppd;
}

/*
 * Open portal for dynamic query
 *
 * Caution: this resets the stmt_mcontext at exit.  We might eventually need
 * to move that responsibility to the callers, but currently no caller needs
 * to have statement-lifetime temp data that survives past this, so it's
 * simpler to do it here.
 */
static Portal
exec_dynquery_with_params(PLpgSQL_execstate *estate,
                          PLpgSQL_expr *dynquery,
                          List *params,
                          const char *portalname,
                          int cursorOptions)
{
    Portal        portal;
    Datum        query;
    bool        isnull;
    Oid            restype;
    int32        restypmod;
    char       *querystr;
    MemoryContext stmt_mcontext = get_stmt_mcontext(estate);

    /*
     * Evaluate the string expression after the EXECUTE keyword. Its result is
     * the querystring we have to execute.
     */
    query = exec_eval_expr(estate, dynquery, &isnull, &restype, &restypmod);
    if (isnull)
        ereport(ERROR,
                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                 errmsg("query string argument of EXECUTE is null")));

    /* Get the C-String representation */
    querystr = convert_value_to_string(estate, query, restype);

    /* copy it into the stmt_mcontext before we clean up */
    querystr = MemoryContextStrdup(stmt_mcontext, querystr);

    exec_eval_cleanup(estate);

    /*
     * Open an implicit cursor for the query.  We use
     * SPI_cursor_open_with_args even when there are no params, because this
     * avoids making and freeing one copy of the plan.
     */
    if (params)
    {
        PreparedParamsData *ppd;

        ppd = exec_eval_using_params(estate, params);
        portal = SPI_cursor_open_with_args(portalname,
                                           querystr,
                                           ppd->nargs, ppd->types,
                                           ppd->values, ppd->nulls,
                                           estate->readonly_func,
                                           cursorOptions);
    }
    else
    {
        portal = SPI_cursor_open_with_args(portalname,
                                           querystr,
                                           0, NULL,
                                           NULL, NULL,
                                           estate->readonly_func,
                                           cursorOptions);
    }

    if (portal == NULL)
        elog(ERROR, "could not open implicit cursor for query \"%s\": %s",
             querystr, SPI_result_code_string(SPI_result));

    /* Release transient data */
    MemoryContextReset(stmt_mcontext);

    return portal;
}

/*
 * Return a formatted string with information about an expression's parameters,
 * or NULL if the expression does not take any parameters.
 * The result is in the eval_mcontext.
 */
static char *
format_expr_params(PLpgSQL_execstate *estate,
                   const PLpgSQL_expr *expr)
{
    int            paramno;
    int            dno;
    StringInfoData paramstr;
    MemoryContext oldcontext;

    if (!expr->paramnos)
        return NULL;

    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));

    initStringInfo(&paramstr);
    paramno = 0;
    dno = -1;
    while ((dno = bms_next_member(expr->paramnos, dno)) >= 0)
    {
        Datum        paramdatum;
        Oid            paramtypeid;
        bool        paramisnull;
        int32        paramtypmod;
        PLpgSQL_var *curvar;

        curvar = (PLpgSQL_var *) estate->datums[dno];

        exec_eval_datum(estate, (PLpgSQL_datum *) curvar,
                        &paramtypeid, &paramtypmod,
                        &paramdatum, &paramisnull);

        appendStringInfo(&paramstr, "%s%s = ",
                         paramno > 0 ? ", " : "",
                         curvar->refname);

        if (paramisnull)
            appendStringInfoString(&paramstr, "NULL");
        else
        {
            char       *value = convert_value_to_string(estate, paramdatum, paramtypeid);
            char       *p;

            appendStringInfoCharMacro(&paramstr, '\'');
            for (p = value; *p; p++)
            {
                if (*p == '\'') /* double single quotes */
                    appendStringInfoCharMacro(&paramstr, *p);
                appendStringInfoCharMacro(&paramstr, *p);
            }
            appendStringInfoCharMacro(&paramstr, '\'');
        }

        paramno++;
    }

    MemoryContextSwitchTo(oldcontext);

    return paramstr.data;
}

/*
 * Return a formatted string with information about PreparedParamsData, or NULL
 * if there are no parameters.
 * The result is in the eval_mcontext.
 */
static char *
format_preparedparamsdata(PLpgSQL_execstate *estate,
                          const PreparedParamsData *ppd)
{
    int            paramno;
    StringInfoData paramstr;
    MemoryContext oldcontext;

    if (!ppd)
        return NULL;

    oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));

    initStringInfo(&paramstr);
    for (paramno = 0; paramno < ppd->nargs; paramno++)
    {
        appendStringInfo(&paramstr, "%s$%d = ",
                         paramno > 0 ? ", " : "",
                         paramno + 1);

        if (ppd->nulls[paramno] == 'n')
            appendStringInfoString(&paramstr, "NULL");
        else
        {
            char       *value = convert_value_to_string(estate, ppd->values[paramno], ppd->types[paramno]);
            char       *p;

            appendStringInfoCharMacro(&paramstr, '\'');
            for (p = value; *p; p++)
            {
                if (*p == '\'') /* double single quotes */
                    appendStringInfoCharMacro(&paramstr, *p);
                appendStringInfoCharMacro(&paramstr, *p);
            }
            appendStringInfoCharMacro(&paramstr, '\'');
        }
    }

    MemoryContextSwitchTo(oldcontext);

    return paramstr.data;
}
